Influence of interface modification on the performance of polymer/Bi2S3 nanorods bulk heterojunction solar cells

In this paper, bulk heterojunction photovoltaic devices based on the poly[2-methoxy-5-(3',7'-dimethyloctyloxy)- 1,4-phenylenevinylene] (MDMO-PPV):Bi2S3 nanorods hybrid material were present. To optimize the performance of the devices, the interface modification of the hybrid material that has a significant impact on the exciton dissociation efficiency was studied. An improvement in the device performance was achieved by modifying the Bi2S3 surface with a thin dye layer. Moreover, modifying the Bi2S3 surface with anthracene-9-carboxylic acid can enhance the performance further. Compared with the solar cells with Bi2S3 nanorods hybrid with the MDMO-PPV as the active layer, the anthracene-9carboxylic acid modified devices are better in performance, with the power conversion efficiency higher by about one order in magnitude.

A Selective-Area Metal Bonding InGaAsP-Si Laser

A 1.55-mu m hybrid InGaAsP-Si laser was fabricated by the selective-area metal bonding method. Two Si blocking stripes, each with an excess-metals accommodated space, were used to separate the optical coupling area and the metal bonding areas. In such a structure, the air gap between the InGaAsP structure and Si waveguide has been reduced to be negligible. The laser operates with a threshold current density of 1.7 kA/cm(2) and a slope efficiency of 0.05 W/A under pulsed-wave operation. Room-temperature continuous lasing with a maximum output power of 0.45 mW is realized.

Self-consistent analysis of AlSb/InAs high electron mobility transistor structures

The influences of channel layer width, spacer layer width, and delta-doping density on the electron density and its distribution in the AlSb/InAs high electron mobility transistors (HEMTs) have been studied based on the self-consistent calculation of the Schrodinger and Poisson equations with both the strain and nonparabolicity effects being taken into account. The results show that, having little influence on the total two dimensional electron gas (2DEG) concentration in the channel, the HEMT's channel layer width has some influence on the electron mobility, with a channel as narrow as 100-130 angstrom being more beneficial. For the AlSb/InAs HEMT with a Te delta-doped layer, the 2DEG concentration as high as 9.1 X 10(12) cm(-2) can be achieved in the channel by enhancing the delta-doping concentration without the occurrence of the parallel conduction. When utilizing a Si delta-doped InAs layer as the electron-supplying layer of the AlSb/InAs HEMT, the effect of the InAs donor layer thickness is studied on the 2DEG concentration. To obtain a higher 2DEG concentration in the channel, it is necessary to use an InAs donor layer as thin as 4 monolayer. To test the validity of our calculation, we have compared our theoretical results (2DEG concentration and its distribution in different sub-bands of the channel) with the experimental ones done by other groups and show that our theoretical calculation is consistent with the experimental results.

Short range scattering mechanism of type-II GaSb/GaAs quantum dots on the transport properties of two-dimensional electron gas

We have studied the scattering process of AlGaAs/GaAs two-dimensional electron gas with the nearby embedded GaSb/GaAs type-II quantum dots (QDs) at low temperature. Quantum Hall effect and Shubnikov-de Haas oscillation were performed to measure the electron density n(2D), the transport lifetime tau(t) and the quantum lifetime tau(q) under various biased gate voltage. By comparing measured results of QDs sample with that of reference sample without embedded QDs, mobilities (transport mobility mu(t) and quantum mobility mu(q)) dominated by GaSb QDs scattering were extracted as functions of n(2D). It was found that the ratios of tau(t) to tau(q) were varying within the range of 1-4, implying the scattering mechanism belonging to the sort of short-range interaction. In the framework of Born approximation, a scattering model considering rectangular-shaped potential with constant barrier height was successfully applied to explain the transport experimental data. In addition, an oscillating ratio of tau(t)/tau(q) with the increasing n(2D) was predicted in the model.

Stable single-mode distributed feedback quantum cascade laser with surface metal grating

A design of single-mode distributed feedback quantum cascade lasers (DFB-QCLs) with surface metal grating is described. A rigorous modal expansion theory is adopted to analyse the interaction between the waveguide mode and the surface plasmon wave for different grating parameters. A stable single-mode operation can be obtained in a wide range of grating depths and duty cycles. The single-mode operation of surface metal grating DFB-QCLs at room temperature for lambda = 8.5 mu m is demonstrated. The device shows a side-mode suppression ratio of above 20 dB. A linear tuning of wavelength with temperature indicates the stable single-mode operation without mode hopping.

ZnO 材料的MOCVD 生长研究

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-04-07T05:45:44Z No. of bitstreams: 1 王振华-ZnO材料的MOCVD生长研究.pdf: 1940715 bytes, checksum: 24795c3f40c326b4bbc7fa587639975e (MD5)

ZnMgO合金材料的MOCVD生长及物性研究

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-04-07T06:58:54Z No. of bitstreams: 1 杨安丽-ZnMgO合金材料的MOCVD生长及物性研究.pdf: 4721220 bytes, checksum: 6fe8feefb955f1426360aab6207d8f74 (MD5)

低维半导体中的自旋极化输运

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-05-27T05:12:54Z No. of bitstreams: 1 毕业论文-刘根华.pdf: 4272809 bytes, checksum: 7d904ae99de7b9a352128318bd30aae5 (MD5)

SrTiO3衬底上MOCVD生长ZnO和InN薄膜

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-02T02:26:43Z No. of bitstreams: 1 贾彩虹.pdf: 7912674 bytes, checksum: c12b25fca62da81c5084da11c9f12e7a (MD5)

新型多段式自脉动DFB 激光器的研制

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-07T01:48:59Z No. of bitstreams: 1 孙瑜博士论文.pdf: 5530964 bytes, checksum: 0821225e6c9c4b1ff4ff037c97424009 (MD5)

新型InP基光逻辑门的研制

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-07T01:50:49Z No. of bitstreams: 1 博士论文张云霄.pdf: 4431523 bytes, checksum: 59d30495b17062d48736bc9cb99098ac (MD5)

基于取样光栅的DFB 激光器阵列研究

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-07T02:53:34Z No. of bitstreams: 1 许晓冬.pdf: 2145982 bytes, checksum: 7aae3967871b6ac7f407e20d087bdb70 (MD5)

InAs/GaAs量子点材料生长及双区结构激光器研究

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-07T06:33:03Z No. of bitstreams: 1 硕士毕业论文-姜立稳.pdf: 5459917 bytes, checksum: fc868ab04b6ddd51dc9e3f7218ee15b9 (MD5)

波长8 μm 分布反馈量子级联激光器的研究

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-07T07:15:25Z No. of bitstreams: 1 张伟--波长 8 μm分布反馈量子级联激光器的研究.pdf: 39254721 bytes, checksum: f62d5575b2849ea4ec14ec33e78dd9f6 (MD5)