Effect of bath temperature on the properties of CuIn_χGa_(1-χ)Se_2 thin films grown by the electrodeposition technique

Electrodeposition is a promising and low cost method to synthesize CuIn_xGa_(1-x)Se_2(CIGS)thin films as an absorber layer for solar cells.The effect of bath temperature on the properties of CIGS thin films was investigated in this paper.CIGS films of 1μm thickness were electrodeposited potentiostatically from aqueous solution,containing trisodium citrate as a complexing agent,on Mo/glass substrate under a voltage of-0.75 V,and bath temperatures were varied from 20 to 60℃.The effects of bath temperature ...     

A 10.7 μm InGaAs/InAlAs Quantum Cascade Detector

A 10.7μm quantum cascade detector based on lattice matched InGaAs/InAlAs/InP is demonstrated and characterized in terms of responsivity, resistivity and detectivity. The device operates in the 8 14μm atmospheric window up to 140 K and shows a peak reponsivity of 14.4mA/W at 78K. With a resistance-area product value of 159Ωcm^2, the Johnson noise limited detectivity D^＊J is 2.8 × 10^9 Jones （cmHz^1/2W^-1） at 78K.     

InAlN合金光致发光峰位能量随温度的异常变化

采用变温的时间积分和时间分辨光致发光方法来研究InAlN的光学性质,随着温度的升高,InAlN合金光致发光峰位能量随温度的变化不是遵循Varshni 公式所预期的变化,而是出现快速红移的现象。我们采用载流子的热激活和热转移模型来拟合了光致发光峰位能量随温度的变化,拟合结果和实验结果符合较好。我们认为峰位随温度的异常变化是由于载流子在深局域态之间的转移造成的,薄膜生长过程中产生的V型缺陷是造成In_0.153Al_0.847N薄膜中出现强局域态的主要原因。     

Surface Emitting Distributed Feedback Quantum Cascade Laser around 8.3 μm

We demonstrate surface emitting distributed feedback quantum cascade lasers emitting at wavelengths from 8.1 μm at 90 K to 8.4 μm at 210 K. The second？order metalized grating is carefully designed using a modified coupled-mode theory and fabricated by contact lithography. The devices show single mode behavior with a side mode suppression ratio above 18 dB at all working temperatures. At 90 K, the device emits an optical power of 101 mW from the surface and 199 mW from the edge. In addition, a double-lobe far-field pattern with a separation of 2.2° is obtained in the direction along the waveguide.     

A Photovoltaic InAs Quantum-Dot Infrared Photodetector

A photovoltaic quantum dot infrared photodetector with InAs/GaAs/AIGaAs structures is reported. The detector is sensitive to normal incident light. At zero bias and 78K, a clear spectral response in the range of 2-7μm has been obtained with peaks at 3.1, 4.8 and 5.7μm. The bandgap energies of GaAs and Al0.2Ga0.8As at 78K are calculated and the energy diagram of the transitions in the Quantum-Dot Infrared Photodetector （QDIP） is given out. The photocurrent signals can be detected up to 110 K, which is state-of-the-art for photovoltaic QDIP, The photovoltaic effect in our detector is a result of the enhanced band asymmetry as we design in the structure.     

基于图形衬底的InAs/GaAs量子点和量子环液滴外延

液滴外延生长半导体材料是一种较为新颖的MBE生长技术,而图形衬底对液滴外延的影响到目前为止并没有非常详细的研究结果. 作者在GaAs μm级别图形衬底上进行了InAs的液滴外延生长,并在不同结构的图形衬底上得到了不同的InAs量子点和量子环生长结果.基于生长结果,分析了图形衬底对液滴外延的影响和液滴外延下量子点和量子环的形成机制以及分布规律.     

Mn离子注入InAs/GaAs量子点结构材料的光电性质研究

用高能离子注入(160keV)的方法对InAs/GaAs量子点结构进行掺杂，研究了不同退火工艺处理后量子点的光致发光和电学性能.相对于长时间退火，快速退火处理后的量子点发光通常较强.在相同的退火条件下，量子点发光峰位随着Mn注入剂量的增加，先是往高能量端快速移动，而后发光峰又往低能方向移动.后者可能是由于Mn原子进入InAs量子点，释放了InAs量子点中的应变所致.对于高注入剂量样品和长时间退火样品，变温电阻曲线在40 K附近会出现反常行为. 关键词： 离子注入 InAs/GaAs量子点 光致发光 团簇     

Low Threshold Current Density Operation of Strain-Compensated Quantum Cascade Laser

We report the low threshold current density operation of strain-compensated In0.64 Ga0.36As/In0.3sAl0.62As quantum cascade lasers emitting near 4.94 μm. By employing an enlarged strain-compensated structure and optimizing the injector doping density, a rather low threshold current density of 0.57kA/cm^2 at 80 K is achieved/or an uncoated 20-μm-wide and 2.5-mm-long laser.     

ZnO Nanostructures Grown on A1N/Sapphire Substrates by MOCVD

ZnO nanorods and nanotubes are successful synthesized on A1N/sapphire substrates by metal-organic chemical vapour deposition （MOGVD）. The different morphology and structure properties of ZnO nanorods and nanotubes are found to be affected by the A1N under-layer. The photoluminescence spectra show the optical properties of the ZnO nanorods and nanotubes, in which a blueshift of UV emission is observed and is attributed to the surface effect.[第一段]     

Effect of Ultraviolet Light on Hybrid Zinc Oxide Polymer Bulk Heterojunction Solar Cells

Compared to conjugated polymer poly[2-methoxy-5-（3＇ ,7＇-dimethyloctyloxy）-l,4-phenylenevinylene] （MDMO-PPV） solar cells, bulk heterojunction solar cells composed of zinc oxide （ZnO） nanocrystals and MDMO-PPV have a better energy conversion efficiency. However, ultraviolet （UV） light deteriorates the performance of solar cells composed of ZnO and MDMO-PPV. We propose a model to explain the effect of UV illumination on these ZnO：MDMO-PPV solar cells. According to this model, the degradation from UV illumination is due to a decrease of exciton dissociation efficiency. Our model is based on the experimentM results such as the measurements of current density versus voltage, photoluminescence, and photocurrent.