高性能InP／InP,InGaAs／InP体材料LP—MOCVD生长

给出利用低压金属有机化合物化学汽相沉积（ＬＰ－ＭＯＣＶＤ）生长技术在ＩｎＰ衬底上生长ＩｎＰ、ＩｎＧａＡｓ的条件，研究了ＩｎＰ／ＩｎＰ的生长特性、ＩｎＧａＡｓ／ＩｎＰ的组份控制、生长特性及生长温度对ＩｎＧａＡｓ特性的影响．发现ＩｎＧａＡｓ／ＩｎＰ最佳生长温度为６４０℃，得到ＩｎＧａＡｓ／ＩｎＰ１６Ｋ光荧光（ＰＬ）谱全高半峰宽为３２．０ｎｍ，ＩｎＰ／ＩｎＰ室温霍尔迁移率为４３６０ｃｍ２／Ｖｓ，背景掺杂浓度为５×１０１４ｃｍ－３，Ｘ光双晶衍射全高半峰宽为２１＂．     

AsCl_3/Ga/H_2系统GaAs外延片的高分辨率深能级瞬态谱研究

用 AsCl_3/Ga/H_2气相外延系统在 GaAs 衬底上生长出GaAs 外延层并制成 Au-GaAs 肖特基结构.利用高分辨率深能级瞬态谱(HDDLTS)仪研究了外延层中深能级的特性.结果表明,缺陷和杂质在外延层中引进若干较高浓度的深能级,经退火后缺陷深能级会被消除.     

Al2O3衬底上低温生长GaN薄膜的一种新方法

研究了 ECR- PAMOCVD在蓝宝石衬底上生长 Ga N外延层时衬底的清洗方法和缓冲层结构对于 Ga N晶体质量的影响 ,提出了新的衬底清洗方法和双缓冲层结构 .实验表明这种方法能够提供一个很好的生长基底 ,可以有效地改善 Ga N外延层的晶体质量     

半绝缘GaAs台阶衬底上GaAs/GaAlAs液相外延生长

本文介绍了在半绝缘GaAs台阶衬底上用SiO_2作为生长掩蔽膜所进行的多层GaAs/GaAlAs液相外延生长(LPE),讨论了SiO_2膜的厚度对外延层几何形貌的影响。并对GaAs台阶衬底上GaAs外延层的生长速率作了理论分析,给出了在底角对角线方向的生长厚度与生长时间的关系式。     

高浓度弛豫SiGe/SOI材料的制备研究

对SOl（绝缘体上的硅）衬底上外延生长的SiGe层进行了研究，并利用透射电镜、AES、Raman光谱、X-ray多晶衍射等技术对SiGe／SOI材料做了表征。结果表明：制备的材料中Ge／Si元素分布均匀，SiGe层是高度弛豫的，SiGe层中应变通过产生失配位错被释放出来。     

GaAs/InP异质材料及MESFET器件研究

用低压金属有机气相外延（LP－MOCVD）在InP衬底上生长出较高质量的GaAs材料，并对材料进行Raman、光致发光（PL）谱的测试分析，结果表明在GaAs／InP外延层中存在伸张应力致使Raman的LO模式的频率红移；PL谱峰较强，16K下测到GaAs的特征激子峰和杂质相关的激子峰，表明了GaAs外延层的晶体质量较好。以此生长方法制备了金属－半导体场效应晶体管（MESFET），其单位跨导可达200ms/mm。该器件已经达到GaAs同质结构的器件水平。     

衬底定向偏差角对非平面衬底液相外延的影响

在非平面衬底液相外延中,衬底的定向偏差角对外延生长有较大影响。为此我们对衬底定向偏差角对外延层形状及表面形貌的影响做了实验研究。 一、实验 1.对外延层形状的影响 我们在衬底定向和(100)面无偏差角(误差在±0.1°范围)及沿沟槽方向和(100)面有0.5°—1°的偏差角的衬底片上,进行液相外延生长四层结构。     

GaP:N外延层特性的研究

本文研究了生长条件对GaP:N外延层的形貌、生长速率、位错密度、S坑密度、氮浓度、少子寿命的影响。实验表明,外延层中的氮浓度、少子寿命随外延生长起始温度的升高而增大。用GaN作为掺杂氮源,在1037—980℃温度范围生长的外延层中氮浓度不高于5.6×10~(17)cm~(-3);LEC GaP衬底(τ_m～5ns)上在995—900℃温度范围生长的外延层,其少子寿命可达～130ns。外延层中的位错密度和衬底中大体相同,但S坑密度降低一个数量级。     

Hg1—xCdxTe液相外延薄膜的貌相分析

用扫描电子显微镜、能量散射Ｘ－射线分析及金相显微镜等方法，研究了Ｈｇ１－ｘＣｄｘＴｅ液相外延薄膜的表面形貌与衬底沾污等的关系，以及外延层夹杂和晶界存在的影响。结果表明，衬底沾污及晶界的存在会使外延薄膜的貌相变差；生长前衬底表面覆盖可以减轻其表面沾污，用适当的回熔ＬＰＥ工艺，可以改进外延层表面形貌及质量     

低压MOCVD法生长GaAs／Si单晶膜及膜的特性研究

本文通过低压ＭＯＣＶＤ方法，采用改进的两步法工艺，即基片表面的高温处理一生长过渡层－退火－外延生长－退火工艺，在向［０１１］方向偏３°的Ｓｉ（１００）衬底上生长了ＧａＡｓ膜，并对外延膜进行了Ｘ射线衍射，喇曼散射和光致发光分析．发现Ｘ射线衍射曲线光滑尖锐，无杂峰，（４００）峰的摇摆曲线很锐，喇曼散射谱中ＴＯ峰与ＬＯ峰的强度比ｌＴＯ／ｌＬＯ很小，光致发光谱的半峰宽只有１２．４ｍｅＶ，说明在Ｓｉ上异质外延的ＧａＡｓ单晶膜具有相当好的质量．     

Undoped semi-insulating indium phosphide (InP) and its applications

During the past several years, the research and de-velopment of InP material has made great progress due to serving as the substrate for most optoelectronic devices operating at the communications wavelength of 1.31 and 1.55 mm. At present, InP has become an important semi-conductor material together with Si and GaAs. When compared to GaAs, InP has higher electron velocity, higher radiation hardness and better heat-conducting property. The advantage of InP crystal material allows higher f…     

Undoped semi-insulating indium phosphide (InP) and its applications

During the past several years, the research and development of InP material has made great progress due to serving as the substrate for most optoelectronic devices operating at the communications wavelength of 1.31 and 1.55 μm. At present, InP has become an important semiconductor material together with Si and GaAs. When compared to GaAs, InP has higher electron velocity, higher radiation hardness and better heat-conducting property. The advantage of InP crystal material allows higher frequency operation and lower power requirements. Therefore, InP is widely being used for the manufacture of microwave devices, high-frequency devices and optoelectronic integrated circuits (OEICs) which are indispensable for wireless technology, satellite communications^[1—3]. Although n-type and p-type InP can meet actual needs, semi-insulating InP substrates remain to be improved due to their poor uniformity and consistency. For this reason, several possible approaches have been reported to the preparation of SI InP by wafer annealing under different conditions^[4—9].     

LP-MOCVD法制备高质量InP薄膜

本文报导以国产三甲基铟(TMIn)和进口的磷烷(PH_3)为源,采用低压金属有机化合物化学气相沉积(LP-MOCVD)方法,在InP衬底上生长高质量InP的工艺条件以及外延层的电学特性和光学特性.     

Defects in NTD InP probed by positron annihilation spectroscopy

Two samples of high purity InP extracted from the same wafer were examined by positron annihilation spectrum analysis after having been, processed by means of thermal Neutron Transmutation Doping (NTD). Compared with the as grown sample with an average positron lifetime of 246 ps at 300 K, the high dose doped one has an average lifetime of 251 ps and the lower dose doped one 248 ps measured under the same condition, indicating that some defects have been introduced in the NTD process. Annealing experimental results show a steady decrease in the average lifetime with increasing annealing temperature up to 550°C. And a peak in lifetime curve around 500°C was observed which may be attributed to defects related structure conversion. Temperature experiments conducted on the low dose doped sample from 150K to 290 K suggest the existence of vacancy-impurity complex which have given rise to an abnormal reduction of average lifetime with increasing temperature. Also a n-type InP sample (A61) was irradiated with thermal neutrons in another reactor and the lifetime results display an increase of 15 ps. Furthermore, to study epithermal neutron irradiation effects on InP, measurements were performed on an n-type InP sample (N119) along with one p-type sample (P118) after having been irradiated with high fluence of epithermal neutrons. The former has an average lifetime of 262 ps and the latter 247 ps after irradiation. The results prove that on some occassion epithermal neutrons can produce sizable defects in InP. Foundation item: Supported by the Science Foundation of Hubei Province (203980532) Biography: WEN Xiang-e (1976-), male, Master candidate, Research direction; majar research interest is defects in semiconductor materials using positron annihilation spectroscopy.     

InAs/GaAs/InP及InAs/InP自组装量子点室温PL谱的研究

用五带 k· p模型计算 In As/ Ga As/ In P及 In As/ In P的室温 PL谱的能级分布 ,分析PL谱峰值 .发现 Ga As的张应变层影响 PL峰值位置 ,与 In As/ In P量子点相比 ,In As/Ga As/ In P量子点 PL谱峰值有明显红移 ,并从能带理论给出解释     

非掺杂半绝缘态InP中补偿缺陷正电子寿命谱的研究

作者利用正电子湮灭寿命谱(PAL)、光激电流瞬态谱(PICTS)及Hall效应,研究了非掺杂半绝缘(SI)InP中补偿缺陷的形成,即在磷化铁(IP)及纯磷(PP)气氛下不同退火条件时其缺陷的发展变化,从而探讨原生非掺InP形成SI态的机制.实验的原始材料都是用液封直拉法(LEC)生长的n型非掺InP.对原生InP,铟空位VIn及与之相关的缺陷是主要的正电子捕获陷阱,VInH4复合体是使材料成为n型材料的原因.在IP SI-InP的形成中,Fe原子扩散进入VIn,可产生替位的补偿缺陷FeIn,Fe的扩散压制     

High-performance thin-film transistors using semiconductor nanowires and nanoribbons

Thin-film transistors (TFTs) are the fundamental building blocks for the rapidly growing field of macroelectronics. The use of plastic substrates is also increasing in importance owing to their light weight, flexibility, shock resistance and low cost. Current polycrystalline-Si TFT technology is difficult to implement on plastics because of the high process temperatures required. Amorphous-Si and organic semiconductor TFTs, which can be processed at lower temperatures, but are limited by poor carrier mobility. As a result, applications that require even modest computation, control or communication functions on plastics cannot be addressed by existing TFT technology. Alternative semiconductor materials that could form TFTs with performance comparable to or better than polycrystalline or single-crystal Si, and which can be processed at low temperatures over large-area plastic substrates, should not only improve the existing technologies, but also enable new applications in flexible, wearable and disposable electronics. Here we report the fabrication of TFTs using oriented Si nanowire thin films or CdS nanoribbons as semiconducting channels. We show that high-performance TFTs can be produced on various substrates, including plastics, using a low-temperature assembly process. Our approach is general to a broad range of materials including high-mobility materials (such as InAs or InP).     

应变补偿和生长停顿对InAs/InAlGaAs/InP纳米结构形貌的影响

利用固源分子束外延（Molecular Beam Epitaxy,MBE）设备生长出InAs/InAlGaAs/InP（001）纳米结构材料,探讨了应变补偿技术和生长停顿对InAs纳米结构形貌的影响.应变补偿技术的引入导致量子点和量子线混合结构的形成,有望成为超宽带半导体激光器的有源区;生长InAs时生长停顿的引入导致尺寸分布均匀的量子线结构的形成,可作为单色激光器有源区.     

不同衬底生长ZnO薄膜的结构与发光特性研究

采用射频磁控溅射方法分别在蓝宝石(Al2O3)(0001)和硅(100)衬底上制备ZnO薄膜．通过X-光衍射测量与分析表明两者都沿C轴方向生长，在Al2O3衬底上的ZnO薄膜结晶质量优于在Si衬底上的薄膜样品．然而，由原子力显微镜观测发现在Al2O3衬底上的薄膜晶粒呈不规则形状，且有孔洞，致密性较差；而在Si衬底上的ZnO薄膜表面呈较规则的三维晶柱，致密性好．光致发光测量表明，不同衬底上生长的ZnO薄膜表现出明显不同的发光行为．     

一种具有平顶陡边响应的长波长光探测器

在PIN型光探测器的基础上制备了一种适用于波分复用系统的具有平顶陡边响应的长波长光探测器。利用低压金属有机化学气相沉积(LP-MOCVD)设备在GaAs衬底上二次外延生长了具有台阶结构的GaAs/AlGaAs滤波腔和InP基PIN光探测器。高质量的GaAs/InP异质外延采用了低温缓冲层生长工艺;具有台阶结构的Fabry-Pérot(F-P)滤波腔采用了纳米量级台阶的制备方法。通过理论计算优化了实现平顶陡边光谱响应特性的器件结构;并通过实验成功制备出了具有平顶陡边响应性能的光探测器,器件的工作波长位于1 549nm,峰值量子效率大于25%,0.5dB光谱响应线宽为3.9nm,3dB光谱响应线宽为4.2nm,响应速率达到17GHz。