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| Record 1 of 27 |
| Author(s): Li, J (Li, Jun); Chang, K (Chang, Kai) |
| Title: Direct detection of the relative strength of Rashba and Dresselhaus spin-orbit interaction: Utilizing the SU(2) symmetry |
| Source: PHYSICAL REVIEW B, 82 (3): Art. No. 033304 JUL 28 2010 |
| Abstract: We propose a simple method to detect the relative strength of Rashba and Dresselhaus spin-orbit interactions in quantum wells (QWs) without relying on the directional-dependent physical quantities. This method utilizes the two different critical gate voltages that leading to the remarkable signals of SU(2) symmetry, which happens to reflect the intrinsic-structure-inversion asymmetry of the QW. We support our proposal by the numerical calculation of in-plane relaxation times based on the self-consistent eight-band Kane model. We find that the two different critical gate voltages leading to the maximum spin-relaxation times [one effect of the SU(2) symmetry] can simply determine the ratio of the coefficients of Rashba and Dresselhaus terms. Our proposal can also be generalized to extract the relative strengths of the spin-orbit interactions in quantum-wire and quantum-dot structures. |
| ISSN: 1098-0121 |
| Article Number: 033304 |
| DOI: 10.1103/PhysRevB.82.033304 |
| Record 2 of 27 |
| Author(s): Ji, HM (Ji, Hai-Ming); Yang, T (Yang, Tao); Cao, YL (Cao, Yu-Lian); Xu, PF (Xu, Peng-Fei); Gu, YX (Gu, Yong-Xian); Wang, ZG (Wang, Zhan-Guo) |
| Title: Self-Heating Effect on the Two-State Lasing Behaviors in 1.3-mu m InAs-GaAs Quantum-Dot Lasers |
| Source: JAPANESE JOURNAL OF APPLIED PHYSICS, 49 (7): Art. No. 072103 Part 1 2010 |
| Abstract: Experimental and theoretical study of the self-heating effect on the two-state lasing behaviors in 1.3-mu m self-assembled InAs-GaAs quantum dot (QD) lasers is presented. Lasing spectra under different injected currents, light-current (L-I) curves measured in continuous and pulsed regimes as well as a rate-equation model considering the current heating have been employed to analyze the ground-state (GS) and excited-state (ES) lasing processes. We show that the self-heating causes the quenching of the GS lasing and the ES lasing by the increased carrier escape rate and the reduced maximum modal gain of GS and ES. (C) 2010 The Japan Society of Applied Physics |
| ISSN: 0021-4922 |
| Article Number: 072103 |
| DOI: 10.1143/JJAP.49.072103 |
| Record 3 of 27 |
| Author(s): Huang, ZL (Huang, Zengli); Wang, JF (Wang, Jianfeng); Liu, ZH (Liu, Zhenghui); Xu, K (Xu, Ke); Yang, H (Yang, Hui); Cao, B (Cao, Bing); Han, Q (Han, Qin); Zhang, GJ (Zhang, Guiju); Wang, CH (Wang, Chinhua) |
| Title: Mechanism on Effect of Surface Plasmons Coupling with InGaN/GaN Quantum Wells: Enhancement and Suppression of Photoluminescence Intensity |
| Source: APPLIED PHYSICS EXPRESS, 3 (7): Art. No. 072001 2010 |
| Abstract: The photoluminescence (PL) intensity enhancement and suppression mechanism on surface plasmons (SPs) coupling with InGaN/GaN quantum wells (QWs) have been systematically studied. The SP-QW coupling behaviors in the areas of GaN cap layer coated with silver thin film were compared at different temperatures and excitation powers. It is found that the internal quantum efficiency (IQE) of the light emitting diodes (LEDs) varies with temperature and excitation power, which in turn results in anomalous emission enhancement and suppression tendency related to SP-QW coupling. The observation is explained by the balance between the extraction efficiency of SPs and the IQE of LEDs. (C) 2010 The Japan Society of Applied Physics |
| ISSN: 1882-0778 |
| Article Number: 072001 |
| DOI: 10.1143/APEX.3.072001 |
| Record 4 of 27 |
| Author(s): Peng, WB (Peng, Wenbo); Zeng, XB (Zeng, Xiangbo); Liu, SY (Liu, Shiyong); Xiao, HB (Xiao, Haibo); Kong, GL (Kong, Guanglin); Yu, YD (Yu, Yude); Liao, XB (Liao, Xianbo) |
| Book Group Author(s): IEEE |
| Title: STUDY OF MICROSTRUCTURE AND DEFECTS IN HYDROGENATED MICROCRYSTALLINE SILICON FILMS |
| Source: 2009 34TH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE, VOLS 1-3: 1049-1053 2009 |
| Book series title: IEEE Photovoltaic Specialists Conference |
| Conference Title: 34th IEEE Photovoltaic Specialists Conference |
| Conference Date: JUN 07-12, 2009 |
| Conference Location: Philadelphia, PA |
| Abstract: Microcrystalline silicon films were deposited by very high frequency (VHF) plasma-enhanced chemical vapor deposition (PECVD) with different hydrogen dilution. The microstructure of these films was investigated using Raman spectroscopy and infrared absorption (IR) spectra. The crystalline, amorphous, and grain boundary volume fractions X-c, X-a and X-gb were estimated from Raman measurements. An interface structure factor (R-if) is proposed to characterize the grain boundary volume fractions in IR spectroscopy. The density of states (DOS) of the microcrystalline crystalline silicon films were studied by phase-shift analysis of modulated photocurrent (MPC) and photoconductivity spectroscopy. It was observed that DOS increases with increasing grain boundary volume fractions, while the values of electron mobility-lifetime product mu T-e(e) disease. |
| ISSN: 0160-8371 |
| ISBN: 978-1-4244-2949-3 |
| Record 5 of 27 |
| Author(s): Bai, YM (Bai YiMing); Wang, J (Wang Jun); Chen, NF (Chen NuoFu); Yao, JX (Yao JianXi); Yin, ZG (Yin ZhiGang); Zhang, H (Zhang Han); Zhang, XW (Zhang XingWang); Huang, TM (Huang TianMao); Wang, YS (Wang YanShuo); Yang, XL (Yang XiaoLi) |
| Title: Quantifying the effectiveness of SiO2/Au light trapping nanoshells for thin film poly-Si solar cells |
| Source: SCIENCE CHINA-TECHNOLOGICAL SCIENCES, 53 (8): 2228-2231 AUG 2010 |
| Abstract: In order to enhance light absorption of thin film poly-crystalline silicon (TF poly-Si) solar cells over a broad spectral range, and quantify the effectiveness of nanoshell light trapping structure over the full solar spectrum in theory, the effective photon trapping flux (EPTF) and effective photon trapping efficiency (EPTE) were firstly proposed by considering both the external quantum efficiency of TF poly-Si solar cell and scattering properties of light trapping structures. The EPTF, EPTE and scattering spectrum exhibit different behaviors depending on the geometric size and density of nanoshells that form the light trapping layer. With an optimum size and density of SiO2/Au nanoshell light trapping layer, the EPTE could reach up to 40% due to the enhancement of light trapping over a broad spectral range, especially from 500 to 800 nm. |
| ISSN: 1674-7321 |
| DOI: 10.1007/s11431-010-4013-5 |
| Record 6 of 27 |
| Author(s): Liu, Y (Liu, Y.); Cheng, F (Cheng, F.); Li, XJ (Li, X. J.); Peeters, FM (Peeters, F. M.); Chang, K (Chang, Kai) |
| Title: Tuning of the two electron states in quantum rings through the spin-orbit interaction |
| Source: PHYSICAL REVIEW B, 82 (4): Art. No. 045312 JUL 22 2010 |
| Abstract: The effect of the Coulomb interaction on the energy spectrum and anisotropic distribution of two electron states in a quantum ring in the presence of Rashba spin-orbit interaction (RSOI) and Dresselhaus SOI (DSOI) is investigated in the presence of a perpendicular magnetic field. We find that the interplay between the RSOI and DSOI makes the single quantum ring behaves like a laterally coupled quantum dot and the interdot coupling can be tuned by changing the strengths of the SOIs. The interplay can lead to singlet-triplet state mixing and anticrossing behavior when the singlet and triplet states meet with increasing magnetic field. The two electron ground state displays a bar-bell-like spatial anisotropic distribution in a quantum ring at a specific crystallographic direction, i.e., [110] or [1 (1) over bar0], which can be switched by reversing the direction of the perpendicular electric field. The ground state exhibits a singlet-triplet state transition with increasing magnetic field and strengths of RSOI and DSOI. An anisotropic electron distribution is predicted which can be detected through the measurement of its optical properties. |
| ISSN: 1098-0121 |
| Article Number: 045312 |
| DOI: 10.1103/PhysRevB.82.045312 |
| Record 7 of 27 |
| Author(s): Zhou, ZW (Zhou, Zhiwen); He, JK (He, Jingkai); Wang, RC (Wang, Ruichun); Li, C (Li, Cheng); Yu, JZ (Yu, Jinzhong) |
| Title: Normal incidence p-i-n Ge heterojunction photodiodes on Si substrate grown by ultrahigh vacuum chemical vapor deposition |
| Source: OPTICS COMMUNICATIONS, 283 (18): 3404-3407 SEP 15 2010 |
| Abstract: We report on normal incidence p-i-n heterojunction photodiodes operating in the near-infrared region and realized in pure germanium on planar silicon substrate. The diodes were fabricated by ultrahigh vacuum chemical vapor deposition at 600 degrees C without thermal annealing and allowing the integration with standard silicon processes. Due to the 0.14% residual tensile strain generated by the thermal expansion mismatch between Ge and Si, an efficiency enhancement of nearly 3-fold at 1.55 mu m and the absorption edge shifting to longer wavelength of about 40 nm are achieved in the epitaxial Ge films. The diode with a responsivity of 0.23 A/W at 1.55 mu m wavelength and a bulk dark current density of 10 mA/cm(2) is demonstrated. These diodes with high performances and full compatibility with the CMOS processes enable monolithically integrating microphotonics and microelectronics on the same chip. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0030-4018 |
| DOI: 10.1016/j.optcom.2010.04.098 |
| Record 8 of 27 |
| Author(s): Xiao, JL (Xiao, Jin-Long); Yang, YD (Yang, Yue-De); Huang, YZ (Huang, Yong-Zhen) |
| Title: Investigation of gain recovery for InAs/GaAs quantum dot semiconductor optical amplifiers by rate equation simulation |
| Source: OPTICAL AND QUANTUM ELECTRONICS, 41 (8): 613-626 JUN 2009 |
| Abstract: The gain recoveries in quantum dot semiconductor optical amplifiers (QD SOAs) are numerically studied by rate equation simulation. Similar to the optical pump-probe experiment, the injection of double 150 fs optical pulses is used to simulate the gain recovery of a weak continuous signal under different injection levels, inhomogeneous broadenings, detuning wavelengths, and pulse signal energies for the QD SOAs. The obtained gain recoveries are then fitted by a response function with multiple exponential terms to determine the response times. The gain recovery can be described by three exponential terms with the time constants, which can be explained as carrier relaxation from the excited state to the ground state, carrier captured by the excited state from the wetting layer, and the supply of the wetting layer carriers. The fitted lifetimes decrease with the increase of the injection currents under gain unsaturation, slightly decrease with the decrease of inhomogeneous broadening of QDs, and increase with the increase of detuning wavelength between continuous signal and pulse signal and the increase of the pulse energy. |
| ISSN: 0306-8919 |
| DOI: 10.1007/s11082-010-9368-0 |
| Record 9 of 27 |
| Author(s): Peng, YS (Peng, Y. S.); Xu, B (Xu, B.); Ye, XL (Ye, X. L.); Niu, JB (Niu, J. B.); Jia, R (Jia, R.); Wang, ZG (Wang, Z. G.) |
| Title: Characterization and analysis of two-dimensional GaAs-based photonic crystal nanocavities at room temperature |
| Source: MICROELECTRONIC ENGINEERING, 87 (10): 1834-1837 OCT 2010 |
| Abstract: This paper describes the design and fabrication process of a two-dimensional GaAs-based photonic crystal nanocavity and analyzes the optical characterization of cavity modes at room temperature. Single InAs/InGaAs quantum dots (QDs) layer was embedded in a GaAs waveguide layer grown on an Al0.7Ga0.3As layer and GaAs substrate. The patterning of the structure and the membrane release were achieved by using electron-beam lithography, reaction ion etching, inductively coupled plasma etching and selective wet etching. The micro-luminescence spectrum is recorded from the fabricated nanocavities, and it is found that some high-order cavity modes are clearly observed besides the lowest-order resonant mode is exhibited in spite of much high rate of nonradiative recombination. The variance of resonant modes is also discussed as a function of r/a ratio and will be used in techniques aimed to improve the probability of achieving spectral coupling of a single QD to a cavity mode. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0167-9317 |
| DOI: 10.1016/j.mee.2009.10.052 |
| Record 10 of 27 |
| Author(s): Sun, YP (Sun, Yuanping); Sun, Y (Sun, Yuanping); Cho, YH (Cho, Yong-Hoon); Wang, H (Wang, Hui); Wang, LL (Wang, Lili); Zhang, SM (Zhang, Shuming); Yang, H (Yang, Hui) |
| Title: Effects of GaN Capping on the Structural and the Optical Properties of InN Nanostructures Grown by Using MOCVD |
| Source: JOURNAL OF THE KOREAN PHYSICAL SOCIETY, 57 (1): 128-132 JUL 2010 |
| Abstract: InN nanostructures with and without GaN capping layers were grown by using metal-organic chemical vapor deposition. Morphological, structural, and optical properties were systematically studied by using atomic force microscopy, X-ray diffraction (XRD) and temperature-dependent photoluminescence (PL). XRD results show that an InGaN structure is formed for the sample with a GaN capping layer, which will reduce the quality and the IR PL emission of the InN. The lower emission peak at similar to 0.7 eV was theoretically fitted and assigned as the band edge emission of InN. Temperature-dependent PL shows a good quantum efficiency for the sample without a GaN capping layers; this corresponds to a lower density of dislocations and a small activation energy. |
| ISSN: 0374-4884 |
| DOI: 10.3938/jkps.57.128 |
| Record 11 of 27 |
| Author(s): Xiong, KL (Xiong, Kanglin); He, W (He, Wei); Lu, SL (Lu, Shulong); Zhou, TF (Zhou, Taofei); Jiang, DS (Jiang, Desheng); Wang, RX (Wang, Rongxin); Qiu, K (Qiu, Kai); Dong, JR (Dong, Jianrong); Yang, H (Yang, Hui) |
| Title: Analysis of lateral current spreading in solar cell devices by spatially-resolved electroluminescence |
| Source: JOURNAL OF APPLIED PHYSICS, 107 (12): Art. No. 124501 JUN 15 2010 |
| Abstract: Spatially-resolved electroluminescence (EL) images from solar cells contain information of local current distribution. By theoretical analysis of the EL intensity distribution, the current density distribution under a certain current bias and the sheet resistance can be obtained quantitatively. Two-dimensional numerical simulation of the current density distribution is employed to a GaInP cell, which agrees very well with the experimental results. A reciprocity theorem for current spreading is found and used to interpret the EL images from the viewpoint of current extraction. The optimization of front electrodes is discussed based on the results. (C) 2010 American Institute of Physics. [doi:10.1063/1.3431390] |
| ISSN: 0021-8979 |
| Article Number: 124501 |
| DOI: 10.1063/1.3431390 |
| Record 12 of 27 |
| Author(s): Yu, JL (Yu, J. L.); Chen, YH (Chen, Y. H.); Ye, XL (Ye, X. L.); Jiang, CY (Jiang, C. Y.); Jia, CH (Jia, C. H.) |
| Title: In-plane optical anisotropy in GaAsN/GaAs single-quantum well investigated by reflectance-difference spectroscopy |
| Source: JOURNAL OF APPLIED PHYSICS, 108 (1): Art. No. 013516 JUL 2010 |
| Abstract: The interface properties of GaNxAs1-x/GaAs single-quantum well is investigated at 80 K by reflectance difference spectroscopy. Strong in-plane optical anisotropies (IPOA) are observed. Numerical calculations based on a 4 band K . P Hamiltonian are performed to analyze the origin of the optical anisotropy. It is found that the IPOA can be mainly attributed to anisotropic strain effect, which increases with the concentration of nitrogen. The origin of the strain component epsilon(xy) is also discussed. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3457901] |
| ISSN: 0021-8979 |
| Article Number: 013516 |
| DOI: 10.1063/1.3457901 |
| Record 13 of 27 |
| Author(s): Zhang, YX (Zhang Yun-Xiao); Liao, ZY (Liao Zai-Yi); Zhao, LJ (Zhao Ling-Juan); Pan, JQ (Pan Jiao-Qing); Zhu, HL (Zhu Hong-Liang); Wang, W (Wang Wei) |
| Title: Monolithic optical gates based on integration of evanescently-coupled uni-traveling-carrier photodiodes and electroabsorption modulators |
| Source: CHINESE PHYSICS B, 19 (7): Art. No. 074216 JUL 2010 |
| Abstract: We report on chip-scale optical gates based on the integration of evanescent waveguide unitraveling-carrier photodiodes (EC-UTC-PDs) and intra-step quantum well electroabsorption modulators (IQW-EAMs) on n-InP substrates. These devices exhibit simultaneously 2.1 GHz and -16.2 dB RF-gain at 21 GHz with a 450 Omega thin-film resistor and a bypass capacitor integrated on a chip. |
| ISSN: 1674-1056 |
| Article Number: 074216 |
| Record 14 of 27 |
| Author(s): Wang, TT (Wang Ting-Ting); Li, WL (Li Wen-Long); Chen, ZH (Chen Zhang-Hui); Miao, L (Miao Ling) |
| Title: Correcting the systematic error of the density functional theory calculation: the alternate combination approach of genetic algorithm and neural network |
| Source: CHINESE PHYSICS B, 19 (7): Art. No. 076401 JUL 2010 |
| Abstract: The alternate combinational approach of genetic algorithm and neural network (AGANN) has been presented to correct the systematic error of the density functional theory (DFT) calculation. It treats the DFT as a black box and models the error through external statistical information. As a demonstration, the AGANN method has been applied in the correction of the lattice energies from the DFT calculation for 72 metal halides and hydrides. Through the AGANN correction, the mean absolute value of the relative errors of the calculated lattice energies to the experimental values decreases from 4.93% to 1.20% in the testing set. For comparison, the neural network approach reduces the mean value to 2.56%. And for the common combinational approach of genetic algorithm and neural network, the value drops to 2.15%. The multiple linear regression method almost has no correction effect here. |
| ISSN: 1674-1056 |
| Article Number: 076401 |
| Record 15 of 27 |
| Author(s): Guo, X (Guo Xi); Wang, YT (Wang Yu-Tian); Zhao, DG (Zhao De-Gang); Jiang, DS (Jiang De-Sheng); Zhu, JJ (Zhu Jian-Jun); Liu, ZS (Liu Zong-Shun); Wang, H (Wang Hui); Zhang, SM (Zhang Shu-Ming); Qiu, YX (Qiu Yong-Xin); Xu, K (Xu Ke); Yang, H (Yang Hui) |
| Title: Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence x-ray diffraction |
| Source: CHINESE PHYSICS B, 19 (7): Art. No. 076804 JUL 2010 |
| Abstract: This paper investigates the major structural parameters, such as crystal quality and strain state of (001)-oriented GaN thin films grown on sapphire substrates by metalorganic chemical vapour deposition, using an in-plane grazing incidence x-ray diffraction technique. The results are analysed and compared with a complementary out-of-plane x-ray diffraction technique. The twist of the GaN mosaic structure is determined through the direct grazing incidence measurement of (100) reflection which agrees well with the result obtained by extrapolation method. The method for directly determining the in-plane lattice parameters of the GaN layers is also presented. Combined with the biaxial strain model, it derives the lattice parameters corresponding to fully relaxed GaN films. The GaN epilayers show an increasing residual compressive stress with increasing layer thickness when the two dimensional growth stage is established, reaching to a maximum level of -0.89 GPa. |
| ISSN: 1674-1056 |
| Article Number: 076804 |
| Record 16 of 27 |
| Author(s): Fu, QY (Fu, Qiuyu); Zhang, WC (Zhang, Wancheng); Lin, QY (Lin, Qingyu); Wu, NJ (Wu, Nanjian) |
| Book Group Author(s): IEEE |
| Title: A Novel CMOS Color Pixel for Vision Chips |
| Source: 2009 IEEE SENSORS, VOLS 1-3: 1562-1565 2009 |
| Conference Title: 8th IEEE Conference on Sensors |
| Conference Date: OCT 25-28, 2009 |
| Conference Location: Christchurch, NEW ZEALAND |
| Abstract: This paper presents a novel CMOS color pixel with a 2D metal-grating structure for real-time vision chips. It consists of an N-well/P-substrate diode without salicide and 2D metal-grating layers on the diode. The periods of the 2D metal structure are controlled to realize color filtering. We implemented sixteen kinds of the pixels with the different metal-grating structures in a standard 0.18 mu m CMOS process. The measured results demonstrate that the N-well/P-substrate diode without salicide and with the 2D metal-grating structures can serve as the high speed RGB color active pixel sensor for real-time vision chips well. |
| ISBN: 978-1-4244-4548-6 |
| Record 17 of 27 |
| Author(s): Guo, JC (Guo Jian-Chuan); Zuo, YH (Zuo Yu-Hua); Zhang, Y (Zhang Yun); Zhang, LZ (Zhang Ling-Zi); Cheng, BW (Cheng Bu-Wen); Wang, QM (Wang Qi-Ming) |
| Title: Theoretical analysis and experimental study of the space-charge-screening effect in uni-traveling-carrier photodiode |
| Source: ACTA PHYSICA SINICA, 59 (7): 4524-4529 JUL 2010 |
| Abstract: A new optimized structure of an UTC (uni-traveling-carrier) photodiode is developed and epitaxied by metal-organic chemical vapor deposition. We fabricated a UTC photodiode of 30 mu m in diameter. Theoretical simulation based on drift-diffusion model was used to analyze the space-charge-screening effect in UTC photodiode primarily in two aspects: the carrier concentrations and the space electric field. The simulation results were generally in agreement with the experimental data. |
| ISSN: 1000-3290 |
| Record 18 of 27 |
| Author(s): Song, GF (Song Guo-Feng); Wang, WM (Wang Wei-Min); Cai, LK (Cai Li-Kang); Guo, BS (Guo Bao-Shan); Wang, Q (Wang Qing); Xu, Y (Xu Yun); Wei, X (Wei Xin); Liu, YT (Liu Yun-Tao) |
| Title: Sub-wavelength beam lasers with surface plasmon structures |
| Source: ACTA PHYSICA SINICA, 59 (7): 5105-5109 JUL 2010 |
| Abstract: The simulation of a plasmonic very-small-aperture laser is demonstrated in this paper. It is an integration of the surface plasmon structure and very-small-aperture laser (VSAL). The numerical results demonstrate that the transmission field can be confined to a spot with subwavelength width in the far field (3.5 mu m far from the emitting surface), and the output power density can be enhanced over 30 times of the normal VSAL. Such a device can be useful in the application of a high resolution far-field scanning optical microscope. |
| ISSN: 1000-3290 |
| Record 19 of 27 |
| Author(s): Luo, J (Luo, J.); Zheng, HZ (Zheng, H. Z.); Shen, C (Shen, C.); Zhang, H (Zhang, H.); Zhu, K (Zhu, K.); Zhu, H (Zhu, H.); Liu, J (Liu, J.); Li, GR (Li, G. R.); Ji, Y (Ji, Y.); Zhao, JH (Zhao, J. H.) |
| Title: Dynamics of photo-enhanced magneto-crystalline anisotropy in diluted ferromagnetic GaMnAs |
| Source: SOLID STATE COMMUNICATIONS, 150 (29-30): 1419-1421 AUG 2010 |
| Abstract: By chopping a pump beam in conventional time-resolved Kerr rotation (TRKR) experiments and measuring the time evolution of M-shaped "major" hysteresis loops of magnetic linear dichroism (Delta MLD = MLDpump-on MLDpump-off), the differential MLD signal in the presence and the absence of the pump beam, we studied the dynamics of photo-enhanced magneto-crystalline anisotropy, and found that its very long recovering time (much longer than 13 ns) might reflect the nature of the coherent coupling between photo-excited holes and localized spins in the d shell of manganese. (C) 2010 Elsevier Ltd. All rights reserved. |
| ISSN: 0038-1098 |
| DOI: 10.1016/j.ssc.2010.04.020 |
| Record 20 of 27 |
| Author(s): Huang, X (Huang, X.); Zhang, XH (Zhang, X. H.); Zhu, YG (Zhu, Y. G.); Li, T (Li, T.); Han, LF (Han, L. F.); Shang, XJ (Shang, X. J.); Ni, HQ (Ni, H. Q.); Niu, ZC (Niu, Z. C.) |
| Title: The effect of an electric field on the nonlinear response of InAs/GaAs quantum dots |
| Source: JOURNAL OF OPTICS, 12 (5): Art. No. 055203 MAY 2010 |
| Abstract: The refractive nonlinearities of InAs/GaAs quantum dots under a dc electric field at photon energies above its band gap energy have been studied using the reflection Z-scan technique. The effect of the dc electric field on the nonlinear response of InAs/GaAs quantum dots showed similar linear and quadratic electro-optic effects as in the linear response regime at low fields. This implies that the electro-optic effect in the nonlinear regime is analogous to the response in the linear regime for semiconductor quantum dots. Our experimental results show the potential for voltage tunability in InAs quantum dot-based nonlinear electro-optic devices. |
| ISSN: 2040-8978 |
| Article Number: 055203 |
| DOI: 10.1088/2040-8978/12/5/055203 |
| Record 21 of 27 |
| Author(s): Wang, GW (Wang Guo-Wei); Xu, YQ (Xu Ying-Qiang); Guo, J (Guo Jie); Tang, B (Tang Bao); Ren, ZW (Ren Zheng-Wei); He, ZH (He Zhen-Hong); Niu, ZC (Niu Zhi-Chuan) |
| Title: Growth and Characterization of GaSb-Based Type-II InAs/GaSb Superlattice Photodiodes for Mid-Infrared Detection |
| Source: CHINESE PHYSICS LETTERS, 27 (7): Art. No. 077305 JUL 2010 |
| Abstract: InAs/GaSb superlattice (SL) midwave infrared photovoltaic detectors are grown by molecular beam epitaxy on GaSb(001) residual p-type substrates. A thick GaSb layer is grown under the optimized growth condition as a buffer layer. The detectors containing a 320-period 8ML/8ML InAs/GaSb SL active layer are fabricated with a series pixel area using anode sulfide passivation. Corresponding to 50% cutoff wavelengths of 5.0 mu m at 77 K, the peak directivity of the detectors is 1.6 x 10(10) cm.Hz(1/2) W-1 at 77 K. |
| ISSN: 0256-307X |
| Article Number: 077305 |
| DOI: 10.1088/0256-307X/27/7/077305 |
| Record 22 of 27 |
| Author(s): Wang, H (Wang, H.); Jiang, DS (Jiang, D. S.); Jahn, U (Jahn, U.); Zhu, JJ (Zhu, J. J.); Zhao, DG (Zhao, D. G.); Liu, ZS (Liu, Z. S.); Zhang, SM (Zhang, S. M.); Yang, H (Yang, H.) |
| Title: Cathodoluminescence study on in composition inhomogeneity of thick InGaN layer |
| Source: THIN SOLID FILMS, 518 (17): 5028-5031 JUN 30 2010 |
| Abstract: We have investigated the optical properties of thick InGaN film grown on GaN by cathodeluminescence (CL) spectroscopy. It is found that there is obvious In composition variation in both growth and lateral direction of InGaN film. The depth distribution of In composition is closely related to the strain relaxation process of InGaN film. Accompanied with the relaxation of compressive strain, the In composition of InGaN layer increases and the CL peak energy shifts towards red. Moreover, a rather apparent In composition fluctuation is found in the relaxed upper part of InGaN layer as confirmed by CL imaging. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0040-6090 |
| DOI: 10.1016/j.tsf.2010.03.163 |
| Record 23 of 27 |
| Author(s): Zhou, HY (Zhou, Huiying); Qu, SC (Qu, Shengchun); Liao, SZ (Liao, Shuzhi); Zhang, FS (Zhang, Fasheng); Liu, JP (Liu, Junpeng); Wang, ZG (Wang, Zhanguo) |
| Title: Optical properties of Mn+ doped GaAs |
| Source: OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS, 4 (6): 784-787 JUN 2010 |
| Abstract: Photoluminescence is one of the most useful techniques to obtain information about optoelectronic properties and defect structures of materials. In this work, Mn-doped GaAs structure materials were prepared by Mn+ ion implantation at room temperature into GaAs. The implanted samples were subsequently annealed at various temperatures under N-2 atmosphere to recrystallize the samples and remove implant damage. The room temperature and low temperature photoluminescence of Mn-doped GaAs were investigated, respectively. A strong peak was found for the sample annealed at 950 degrees C for 5 s. Transitions near 0.989 eV (1254 nm), 1.155 eV (1074 nm) and 1.329 eV (933nm) were identified and formation of these emissions was analyzed for all prepared samples. This structure material could have myriad applications, including information storage, magneto-optical properties and energy level engineering. |
| ISSN: 1842-6573 |
| Record 24 of 27 |
| Author(s): Liu, JM (Liu, J. M.); Liu, XL (Liu, X. L.); Xu, XQ (Xu, X. Q.); Wang, J (Wang, J.); Li, CM (Li, C. M.); Wei, HY (Wei, H. Y.); Yang, SY (Yang, S. Y.); Zhu, QS (Zhu, Q. S.); Fan, YM (Fan, Y. M.); Zhang, XW (Zhang, X. W.); Wang, ZG (Wang, Z. G.) |
| Title: Measurement of w-InN/h-BN Heterojunction Band Offsets by X-Ray Photoemission Spectroscopy |
| Source: NANOSCALE RESEARCH LETTERS, 5 (8): 1340-1343 AUG 2010 |
| Abstract: X-ray photoelectron spectroscopy has been used to measure the valence band offset (VBO) of the w-InN/h-BN heterojunction. We find that it is a type-II heterojunction with the VBO being -0.30 +/- A 0.09 eV and the corresponding conduction band offset (CBO) being 4.99 +/- A 0.09 eV. The accurate determination of VBO and CBO is important for designing the w-InN/h-BN-based electronic devices. |
| ISSN: 1931-7573 |
| DOI: 10.1007/s11671-010-9650-x |
| Record 25 of 27 |
| Author(s): Zhou, XL (Zhou, X. L.); Chen, YH (Chen, Y. H.); Liu, JQ (Liu, J. Q.); Jia, CH (Jia, C. H.); Zhou, GY (Zhou, G. Y.); Ye, XL (Ye, X. L.); Xu, B (Xu, Bo); Wang, ZG (Wang, Z. G.) |
| Title: Temperature dependent photoluminescence of an In(Ga)As/GaAs quantum dot system with different areal density |
| Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS, 43 (29): Art. No. 295401 JUL 28 2010 |
| Abstract: We have systematically studied the temperature dependent photoluminescence of a self-assembled In(Ga)As/GaAs quantum dot (QD) system with different areal densities from similar to 10(9) to similar to 10(11) cm(-2). Different carrier channels are revealed experimentally and confirmed theoretically via a modified carrier equation model considering a new carrier transfer channel, i.e. continuum states ( CS). The wetting layer is demonstrated to be the carrier quenching channel for the low-density QDs but the carrier transfer channel for the high-density QDs. In particular, for the InGaAs/GaAs QDs with a medium density of similar to 10(10) cm(-2), the CS is verified to be an additional carrier transfer channel in the low temperature regime of 10-60 K, which is studied in detail via our models. The possible carrier channels that act on different temperature regimes are further discussed, and it is demonstrated that density is not a crucial factor in determining the carrier lateral coupling strength. |
| ISSN: 0022-3727 |
| Article Number: 295401 |
| DOI: 10.1088/0022-3727/43/29/295401 |
| Record 26 of 27 |
| Author(s): He, LJ (He, Lingjuan); Xu, XM (Xu, Xuming); Liu, NH (Liu, Nianhua); Yu, TB (Yu, Tianbao); Fang, LG (Fang, Liguang) |
| Title: Ultracompact triplexer by coupling and decoupling of multiple photonic crystal waveguides |
| Source: JOURNAL OF OPTICS, 12 (6): Art. No. 065502 JUN 2010 |
| Abstract: We investigate numerically the self-imaging effect in a system of multiple coupled photonic crystal waveguides (M-CPCWs) with asymmetric coupling. Then two couplers of 2-CPCWs and 3-CPCWs are cascaded to form an ultracompact triplexer by employing coupling and decoupling of M-CPCWs. The wavelength of 1310 nm propagates along the input direction because the M-CPCWs are decoupled at the same decoupling frequency. The other two wavelengths (1490 and 1550 nm) are separated by combining multimode interference and the dual mode coupling effect. Only by introducing a single defect near the crossing point between two output photonic crystal waveguides (PCWs) are the high extinction ratios for the three wavelengths achieved simultaneously. |
| ISSN: 2040-8978 |
| Article Number: 065502 |
| DOI: 10.1088/2040-8978/12/6/065502 |
| Record 27 of 27 |
| Author(s): Zheng, GL (Zheng, Gaolin); Wang, J (Wang, Jun); Liu, XL (Liu, Xianglin); Yang, AL (Yang, Anli); Song, HP (Song, Huaping); Guo, Y (Guo, Yan); Wei, HY (Wei, Hongyuan); Jiao, CM (Jiao, Chunmei); Yang, SY (Yang, Shaoyan); Zhu, QS (Zhu, Qinsheng); Wang, ZG (Wang, Zhanguo) |
| Title: Valence band offset of MgO/TiO2 (rutile) heterojunction measured by X-ray photoelectron spectroscopy |
| Source: APPLIED SURFACE SCIENCE, 256 (23): 7327-7330 SEP 15 2010 |
| Abstract: The valence band offset (VBO) of MgO/TiO2 (rutile) heterojunction has been directly measured by Xray photoelectron spectroscopy. The VBO of the heterojunction is determined to be 1.6 +/- 0.3 eV and the conduction band offset (CBO) is deduced to be 3.2 +/- 0.3 eV, indicating that the heterojunction exhibits a type-I band alignment. These large values are sufficient for MgO to act as tunneling barriers in TiO2 based devices. The accurate determination of the valence and conduction band offsets is important for use of MgO as a buffer layer in TiO2 based field-effect transistors and dye-sensitized solar cells. (C) 2010 Elsevier B. V. All rights reserved. |
| ISSN: 0169-4332 |
| DOI: 10.1016/j.apsusc.2010.05.074 |
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