【作者】 杨智慧；

【导师】 秦福文；

【作者基本信息】 大连理工大学 ， 微电子与固体电子学， 2010， 硕士

【摘要】 以氮化镓(GaN)为代表的Ⅲ族氮化物半导体材料,由于其在光电子和微电子器件上的应用前景,受到了人们极大的关注。2002年的研究表明,氮化铟(InN)的禁带宽度为0.7eV,而不是之前报道的1.89eV,这就意味着通过调节InxGa1_xN三元合金的In组分,可使其禁带宽度从3.39eV(GaN)到0.7eV(InN)连续可调,其对应的吸收光谱的波长从紫外部分(366nm)可以一直延伸到近红外部分(1771nm),几乎完整覆盖了整个太阳光谱。理论上预测,如果用InxGa1-xN做成叠层太阳能电池,其效率可达72%。然而,要想获得高效率的InGaN太阳电池,制备In组分连续可调的InGaN薄膜是关键,这就要求首先制备高质量的GaN和InN薄膜。本实验是在自行研制的配有反射式高能电子衍射(RHEED)装置的电子回旋共振-等离子体增强金属有机物化学气相沉积(ECR-PEMOCVD)装置上进行的。实验分为两部分：1.采用高纯氮气(N2)为氮源,利用三甲基镓(TMGa)为镓源,在掺铝氧化锌(ZnO：Al)透明导电柔性衬底上生长GaN薄膜；2.采用高纯氮气(N2)为氮源,利用三甲基铟(TMIn)为铟源,在α-Al2O3衬底上生长InN薄膜。利用RHEED、X射线衍射(XRD)和原子力显微镜(AFM)表征薄膜的晶体结构和表面形貌,利用室温光透射谱表征薄膜的光学性质,室温霍尔效应表征薄膜的电学性质,利用拉曼光谱表征薄膜的晶格振动。ZnO：Al衬底上生长的GaN薄膜,在200～500℃温度范围内,具有c轴择优取向的钎锌矿结构,结晶性较好；薄膜表面形貌较为平整；在最佳温度下(450℃)生长的GaN薄膜的光谱透过率为85～90%,禁带宽度为3.45eV。a-Al203衬底上生长的InN薄膜,在350～550℃温度范围,0.4～1.0sccm的TMIn流量范围内,具有良好的(0002)择优取向,且薄膜为单一晶相；拉曼光谱中有显著的A1(LO)和E2 (High)模式；室温载流子迁移率为10～40cm2／v.s,背景方块载流子浓度为1016左右。更多还原

【Abstract】 Due to their great potential use in optoelectronic and microelectronic devices, GaN-based III nitrides semiconductor materials have been widely investigated. In 2002, it has been reported that the optical band gap of InN is 0.7eV, not the commonly quoted value 1.89 eV. This means that the band gap of InxGa1-xN ternary alloy can be continuously tuned from 3.4eV (GaN) to 0.7eV (InN). by adjusting the In fractions. The corresponding absorption spectrum can be stretched from the ultraviolet part (366nm) to nearly infrared part (1771nm), covering almost the whole solar absorption spectrum. It is predicted that the efficiency of the InGaN tandem solar cell can be up to 72%. Therefore, study on the InGaN solar cell will be of great value.In order to obtain high efficiency InGaN solar cell, it is essential to prepare high-quality InGaN films in which the In fractions can be tuned. However, it requires the preparation of high-quality GaN and InN films at the first step.The experiments were carried out on the Electron Cyclotron Resonance-Plasma Enhanced Metal Organic Chemistry Vapor Deposition (ECR-PEMOCVD) system equipped with in-situ Reflection High Energy Electron Diffraction (RHEED). The experiments were classified into two parts:1. Using trimethyl-gallium(TMGa) as Ga source, high purity N2 as N source, GaN films were deposited on ZnO:Al layer; 2. Using trimethyl-indium(TMIn) as In source, high purity N2 as N source, InN films were deposited onα-Al2O3 substrate.The crystal structure and surface topography of the films were characterized by RHEED, x-ray diffraction (XRD) and atomic force microscope (AFM). The electrical properties of the films were investigated by Hall measurements. The lattice vibration was characterized by Raman spectra.GaN films deposited at 200～500℃are of high c-axis preferred orientation and have good crystalline characteristic. The surface morphology of GaN films is smooth. The optical transmittance and band gap at the optimal growth temperature is 85～90% and 3.45 eV, respectively.InN films deposited at the temperature range of 350～550℃and a TMIn flux range of 0.4～1.0 sccm exhibited high (0002) preferred orientation and good wurtzite-type structure. Raman studied showed that there are significant A1 (LO) and E2 (High) models. The room temperature carrier mobility rate is 10～40cm2/v·s, and sheet concentration is about 1016 obtained by Hall measurement.更多还原