Ⅱ-Ⅵ族宽禁带蓝绿色发光器材料的MBE研究

本文报道ＺｎＳｅ基ⅡⅥ族宽带发光材料分子束外延系统的建立、ｐ型掺杂用等离子体活性氮源的研制、两性掺杂的ＺｎＳｅ材料的生长。实验证明国产ＭＢＥ设备能够自洽生长优质ＺｎＳｅ单晶薄膜；用自制的等离子体活性氮源作受主掺杂剂，获得了ｐＺｎＳｅ单晶薄膜，经ＣＶ测量发现，［Ｎａ］［Ｎｄ］高达～５×１０１７·ｃｍ－３；用国产粉末状ＺｎＣｌ２源作施主掺杂剂，获得了ｎＺｎＳｅ单晶薄膜，Ｈａｌ测量表明［ｎ］高达～２３×１０１９·ｃｍ－３。生长速度均控制在～０５μｍ／ｈ。     

静压下（CdSe）m／（ZnSe）n—ZnSe超短周期超晶格量子阱的共振…

在静压和液氮温度下观察到（ＣｄＳｅ）ｍ／（ＺｎＳｅ）ｎ短周期超晶格中重空穴激子的复合发光和多达４阶的类ＺｎＳｅＬＯ多声子喇曼散射，并观察到厚ＺｎＳｅ势垒层的带边发光和限制在厚势垒层中的类ＺｎＳｅＬＯ声子散射。结果表明，加压后（ＣｄＳｅ）ｍ／（ＺｎＳｅ）ｎ短周期超晶格中的类ＺｎＳｅ的１ＬＯ和２ＬＯ声子模频率分别以３．７６和７．１１ｃｍ＾－１／ＧＰａ的速率向高频方向移动，超晶格阱层光致发光峰的压力系数     

超高真空化学气相淀积法生长的n-Si/i-p~+-i SiGe/n-Si结构的透射电镜和二次离子质谱分析

本文用透射电镜（ＸＴＥＭ）和二次离子质谱（ＳＩＭＳ）分析了由超高真空化学气相淀积法（ＵＨＶＣＶＤ）生长的ｎ－Ｓｉ／ｉ－ｐ＋－ｉＳｉＧｅ／ｎ－Ｓｉ结构，发现在硅上外延生长ｉ－ｐ＋－ｉＳｉＧｅ时，在靠近Ｓｉ的ｉ／ｐ＋ＳｉＧｅ界面处存在一个很薄的层，但在ｉ－ｐ＋－ｉＳｉＧｅ上外延生长Ｓｉ时，无此现象产生．此薄层是由在硅上外延生长ｉ－ｐ＋－ｉＳｉＧｅ时硼原子聚集在靠近Ｓｉ的ｉ／ｐ＋ＳｉＧｅ界面处形成的高掺杂薄层．高掺杂的薄层影响由此结构制备的异质结双极晶体管（ＨＢＴ）的ＢＣ结的正向导通电压．     

ZnCdSe—ZnSe／CaF2多量子阱中的三阶非线性

我们首次利用Ｚ－扫描技术在室温下研究了ＺｎＣｄＳｅ－ＺｎＳｅ／ＣａＦ２多量子了进中的三阶非线性，得到非线性系数ｎ２为－４．４６×１０＾－８ｅｓｕ。其主要非线性机理归结为ＺｎＣｄＳｅ－ＺｎＳｅ／ＣａＦ２多量子阱中的带填充效应。     

等离子体活性氮源的研制

ＺｎＳｅ基材料是研制蓝绿色发光器首选材料之一。本文报道一种自己研制的，以石英管为主体结构材料的，可适用于ＺｎＳｅ基材料分子束外延掺杂的简易等离子体活性氮源。该氮源采用射频激励方式激活氮分子。在适当生长条件，利用装备有该氮源的国产ＦＷ－Ⅲ型分子束外延设备，成功地生长出Ｐ型ＺｎＳｅ优质单晶薄膜，ＳＩＭＳ测量表明，薄膜中氮浓度高达～２．３×１０＾２０ｃｍ＾－３，Ｃ－Ｖ测量表明，净空穴浓度（Ｎａ）－（Ｎｄ     

9μmp^＋—GexSi1—x／p—Si异质结内光电红外探测器

用分子束外延方法生长了ｐ＾＋－ＧｅｘＳｉ１－ｘ／ｐ－Ｓｉ异质结，并用平面工艺制成了内光电红外探测器，器件截止响应波长达９μｍ，在５２Ｋ时，Ｒｖ５００Ｋ＝３．３×１０＾３Ｖ／Ｗ。     

用于功率器件的P型厚高阻外延片

本文论述在常压ＣＶＤ硅外延系统中，通过ｅ＿ｑＰ＝Ｂ－Ａ／Ｔ，分别计算出ＳｉＨ－Ｃｌ＿３、ＰＣｌ＿３和ＢＣｌ＿３的Ａ和Ｂ二常数值。采用低温深冷工艺，进一步提高硅源的纯度，通过控制ＳｉＨＣｌ＿３的蒸汽压，在晶向为（１１１）和（１００），掺硼电阻率（４～８）×１０￣（－３）Ω·ｃｍ的抛光衬底硅片上，生长出外延层电阻率为３５０Ω·ｃｍ（杂质浓度３．５×１０￣（１３）／ｃｍ￣３），外延层厚度达１２０μｍ的ｐ／ｐ￣＋／硅外延片，制成器件的击穿电压可达１０００Ｖ。     

Si基Ge0.85Si0.15异质光电二极管

采用低温生长缓冲层,高温生长ＧｅＳｉ外延层的方法在ｎ型Ｓｉ衬底上外延生长（ｉ）Ｇｅ０．８５Ｓｉ０．１５－（ｐ）Ｓｉ层,以此材料作为吸收区制备成ＧｅＳｉ／Ｓｉ异质结ｐｉｎ台面光电二极管。其波长范围为０．７－１．５５μｍ,峰值波长位于１．０６μｍ,暗电流密度低达０．０３３μＡ／ｍｍ＾２（－２Ｖ）,在１．０６μｍ和１．３μｍ处的响应度分别为１．８Ａ／Ｗ（－２Ｖ）和０．０６６Ａ／Ｗ（－Ｖ）。     

Zn—Se—Te三元系富Te区的液固平衡以及ZnSe0.52Te0.48薄膜在（100）In…

本文运用Ｒ．Ａ．Ｓ（Ｒｅｇｕｌａｒ Ａｓｓｏｃｉａｔｅｄ Ｓｏｌｕｔｉｏｎｓ）模型的基本原理，导出了简明的适用于Ａ＾ＩＩ－Ｂ＾Ｖｉ－Ｃ＾ＶＩ三元系富ＶＩ族区的液固平衡方程，并由此计算了Ｚｎ－Ｓｅ－Ｔｅ三元系富Ｔｅ区的液固平衡曲线，计算结果与已有的实验数据符合，最后，对ＺｎＳｅ０．５２Ｔｅ０．４８在（１００）ＩｎＰ衬底上的液相外延生长进行了实验研究。     

静压下（CdSe）_m／（ZnSe）_n－ZnSe超短周期超晶格量子阱的共振喇曼散射研究

在静压和液氮温度下观察到（ＣｄＳｅ）ｍ／（ＺｎＳｅ）ｎ短周期超晶格中重空穴激子的复合发光和多达４阶的类ＺｎＳｅＬＯ多声子喇曼散射，并观察到厚ＺｎＳｅ势垒层的带边发光和限制在厚势垒层中的类ＺｎＳｅＬＯ声子散射．结果表明，加压后（ＣｄＳｅ）ｍ／（ＺｎＳｅ）ｎ短周期超晶格中的类ＺｎＳｅ的１ＬＯ和２ＬＯ声子模频率分别以３．７６和７．１１ｃｍ－１／ＧＰａ的速率向高频方向移动，超晶格阱层光致发光峰的压力系数为５９．８ｍｅＶ／ＧＰａ．与（ＣｄＳｅ）ｍ／（ＺｎＳｅ）ｎ短周期超晶格共振时的类ＺｎＳｅ１ＬＯ声子模频率比与ＺｎＳｅ势垒层共振时的类ＺｎＳｅ１ＬＯ声子模频率低２．０ｃｍ－１，反映了（ＣｄＳｅ）ｍ／（ＺｎＳｅ）ｎ短周期超晶格中ＬＯ声子的限制效应     

Heavy Cr doping of ZnSe by molecular beam epitaxy

Epitaxial ZnSe layers were grown by molecular beam epitaxy (MBE) to study Cr incorporation with the long-term goal of demonstrating an alternate route for achieving transition-metal-doped lasers. Concentrations between 10¹⁵ atoms cm⁻³ and 4×10²⁰ atoms cm⁻³ were achieved. Secondary ion-mass spectroscopy (SIMS) concentration profiles strongly suggest that surface segregation and accumulation of Cr occurs during growth. Photoluminescence (PL) measurements indicate Cr is incorporated in the optically active Cr²⁺ state up to levels of ∼10¹⁹ cm⁻³. Electron paramagnetic resonance (EPR) studies suggest that the Cr atoms exhibit collective magnetic behavior even at these levels. X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED) indicate high structural quality is maintained for Cr incorporation for levels up to ∼10¹⁹ atoms cm⁻³.     

掺氮ZnSe外延层的光致发光研究

报导了掺氮ＺｎＳｅ外延层的光致发光,研究了与氮受主有关的发光峰随温度和激发强度的变化关系．１０Ｋ下施主－受主对发光峰随激发强度的增加向高能方向移动,且峰强呈现饱和趋势．在１０～３００Ｋ温度范围光致发光谱表明,随着温度增加,由于激子在受主束缚激子态和施主束缚激子态之间转移,施主束缚激子发光峰强度相对受主束缚激子发光峰强度增加     

Chemical etching of ZnSe crystals

Our report describes a newly developed chemical etchant suitable for producing mirror-like ZnSe surfaces. A mirror surface without any scratch obtained through lapping and polishing was produced by etching in a KMnO₄(100 mg)/ H₂SO₄(10 ml)/H₂O(40 ml) solution. The etching rate of ZnSe used in this case was about 1 um/min. The etchant could be applied to crystals with (lll)A, (lll)B, and (100) faces and the etching rate similar for each face. The value of the full width at half maximum in the x-ray rocking curve decreased by half after etching with the KMnO₄-system etchant.     

关于准一维ZnSe纳米结构的合成与应用

硒化锌是Ⅱ-Ⅵ族中重要的宽禁带半导体材料,其禁带宽度为2.7 eV,是理想的蓝光探测器材料。准一维ZnSe纳米结构的合成有多种,如纳米带、纳米线、纳米棒等。由于纳米材料与薄膜材料相比具有表面积大、量子效应等独特的物理及化学特性,使得基于纳米材料的纳米器件在过去的几年内被广泛的制备与研究。目前准一维ZnSe纳米材料已经制备出多种纳米器件,文中将对ZnSe纳米结构的合成以及应用作介绍。     

The study of nitrogen doping in ZnSe and ZnSe:Te

A comparative study of nitrogen doping in ZnSe and ZnTe has been performed and the results suggest that dopant solubility seems to be the limiting factor, at least under our growth conditions, in obstructing degenerate p-type doping of ZnSe. In an effort to increase the nitrogen acceptor concentration in ZnSe, we have investigated the effects of Te isoelectronic impurity on the nitrogen doping concentration in ZnSe. It was found that the total nitrogen concentration and the nitrogen acceptor concentration are indeed increased, but the room temperature free hole concentration actually drops slightly. Temperature dependent transport measurements were performed and the results show a large increase in compensation ratio as well as a dramatical reduction in hole mobility. The latter is attributed to the tendency for hole localization at the isoelectronic impurity.     

Atomic layer epitaxy of nitrogen-doped ZnSe

Atomic layer epitaxy of nitrogen-doped ZNSe was studied. The ZnSe films were grown on GaAs(00l) substrates at 250°C with a continuous flow of nitrogen and alternate supplies of zinc and selenium. The grown films were characterized by photoluminescence spectra at 4.2K, and it was found that nitrogen was incorporated as a shallow acceptor in the films. The Schottky diodes were prepared by evaporating gold on the nitrogen-doped films grown on p-type GaAs substrates. A rectifying characteristic that was consistent with the structure, assuming p-type conductivity of ZnSe, was observed. Capacitance-voltage measurement of the structure also indicated p-type conductivity of the films.     

ZnSe制备技术研究进展

ZnSe是一种很有应用前景的半导体光电材料,得到了广泛的关注,制备高质量的ZnSe已成为光电 技术领域重要的研究课题之一.本文详细叙述了近年来ZnSe的各种制备技术的研究进展及其特点.     

N-型ZnSe:Cl的分子束外延生长

本文报道利用分子束外延(MBE)技术,采用高纯ZnCl_2作掺杂源,成功地进行了n—型ZnSe:Cl的分子束外延生长。n-ZnSe:Cl/p-GaAs异质结构的伏-安(I—V)特性和热探针测试显示外延层呈n型导电特性。反射高能电子衍射(RHEED)和x射线衍散谱测量表明ZnSe:Cl外延层具有较好的晶体质量。     

Low pressure MOVPE growth of ZnSe,ZnTe, and ZnSe/ZnTe strained-layer superlattices

ZnSe and ZnTe single-crystal layers have been grown onto (100) GaAs substrates by low-pressure metalorganic vapor-phase epitaxy (LP-MOVPE) using the triethylamine-dimethylzinc adduct [DMZn(NEt₃)] as the zinc precursor. The selenium and tellurium precursors were H₂Se (5% in H₂) and di-isopropyltellurium (DiPTe), respectively. These two semiconductors have been grown with different VI/II molar ratios, at different growth temperatures, and with an overall growth pressure ranging from 40 to 400 Torr. Optimal growth parameters have been determined by optical means for the two materials. This information was then used to grow ZnTe/ZnSe strained-layer superlattices. We have studied structures grown on both ZnSe and ZnTe relaxed buffer layers which display a drastic dependence of the Stokes shift between photoluminescence and the optical bandgap on the nature of the buffer layer. Growth interruptions have been used to optimize the optical properties of the superlattices. Theoretical modeling of superlattice band structures has been performed using results of optical and structural characterizations. Observations of zone center transitions as well as excitons associated with the miniband dispersion of the superlattices are reported, in agreement with the theoretical calculation.