用卢瑟福背散射/沟道技术研究ZnO/Zn0.9Mg0.1O/ZnO异质结的弹性应变

利用卢瑟福背散射/沟道技术对射频等离子体辅助分子束外延法生长在蓝宝石衬底上的ZnO/Zn_0.9Mg_0.1O/ZnO异质结进行了组分分析，并得到了异质结弹性应变随深度的变化，应变由界面向表面逐渐释放，并由负变正，且在ZnO与Zn_0.9Mg_0.1O界面处轻微增大.负的应变是由于ZnO与衬底的晶格失配和热失配，而逐渐变为正值是Zn_0.9Mg_0.1O与ZnO的晶格常数差异及弹性应变的 关键词： 异质结 卢瑟福背散射/沟道 弹性应变 ZnMgO     

用卢瑟福背散射/沟道技术及高分辨X射线衍射技术分析不同Al和In含量的AlInGaN薄膜的应变

利用卢瑟福背散射/沟道技术对在蓝宝石衬底上用金属有机化学气相沉积方法生长的有GaN缓冲层(>2μm)的一系列不同Al和In含量的AlInGaN薄膜进行组分及结晶品质的测量；并结合高分辨X射线衍射技术，通过对AlInGaN的对称(0002)面，及非对称(1015)面的θ—2θ扫描及倒空间扫描，可以精确测定AlInGaN外延层的晶格常数及水平和垂直方向的应变.实验结果表明AlInGaN 薄膜中不同含量Al和In对其应变有较大的影响，结合Vegard定理，对这一现象给出了理论的解释. 关键词： AlInGaN 高分辨X射线衍射 卢瑟福背散射/沟道 弹性应变     

用电化学沉积法制备ZnO/Cu2O异质p-n结

由于P型ZnO的制备仍然存在一定的困难,限制了ZnO在光电方面的应用,尤其是在发光二极管和激光器的实际应用,目前利用P型的透明半导体氧化物与n型ZnO制备异质p-n结,成为新的研究热点。选择P型导电Cu2O与ZnO制备出异质p-n结。Cu2O是一种典型的P型半导体材料,禁带宽度为2．1eV,可见光范围的吸收系数较高。首次利用电化学沉积的方法制备了ZnO／Cu2O异质p-n结,研究了电沉积ZnO,Cu2O的生长机制和ZnO／Cu2O异质结的结构、光学和电学特性。     

Si(111)衬底上生长有多缓冲层的六方GaN晶格常数计算和应变分析

利用卢瑟福背散射/沟道技术和高分辨率X射线衍射技术对在Si(111)衬底上利用金属有机化合物气相外延技术(MOVPE)生长有多缓冲层的六方GaN外延膜进行结晶品质计算、晶格常数计算和应变分析. 实验结果表明：GaN外延膜的结晶品质为χ_min=1.54%，已达到完美晶体的结晶品质(χ_min=1%—2%)；GaN外延膜的水平方向和垂直方向晶格常数分别为：a_epi＝0.31903nm，c_epi=0.51837nm，基本达到G 关键词： GaN 高分辨X射线衍射 卢瑟福背散射/沟道 弹性应变     

Cu_2O/ZnO氧化物异质结太阳电池的研究进展

介绍了近年来低成本Cu_2O/ZnO氧化物异质结太阳电池方面的研究进展.应用于光伏器件的吸收层材料Cu_2O是直接带隙半导体材料,天然呈现p型;其原材料丰富,且对环境友好.Cu_2O/ZnO异质结太阳电池结构主要有平面结构和纳米线/纳米棒结构.纳米结构的Cu_2O太阳电池提高了器件的电荷收集作用;通过热氧化Cu片技术获得的具有大晶粒尺寸平面结构Cu_2O吸收层在Cu_2O/ZnO太阳电池应用中展现出了高质量特性.界面缓冲层(如i-ZnO,a-ZTO,Ga_2O_3等)和背表面电场(如p~+-Cu_2O层等)可有效地提高界面处能级匹配和增强载流子输运.10 nm厚度的Ga_2O_3提供了近理想的导带失配,减少了界面复合;Ga_2O_3非常适合作为界面层,其能够有效地提高Cu_2O基太阳电池的开路电压V_(oc)(可达到1.2 V)和光电转换效率.p~+-Cu_2O(如Cu_2O:N和Cu_2O:Na)能够减少器件中背接触电阻和形成电子反射的背表面电场(抑制电子在界面处复合).利用p型Na掺杂Cu_2O(Cu_2O:Na)作为吸收层和Zn_(1-x)Ge_x-O作为n型缓冲层,Cu_2O异质结太阳电池(器件结构:MgF_2/ZnO:Al/Zn_(0.38)Ge_(0.62)-O/Cu_2O:Na)光电转换效率达8.1%.氧化物异质结太阳电池在光伏领域展现出极大的发展潜力.     

ZnO/ZnMgO异质结场效应管的制备与性能研究

利用等离子体增强化学气相沉积(PECVD)技术,在ZnO/ZnMgO异质结构上制备SiO₂作为栅绝缘层,采用光刻与腐蚀工艺制备ZnO/ZnMgO异质结场效应管。电学性能测试及计算结果表明器件栅压调控作用明显。发现栅端漏电流对器件性能造成一定影响。在低温条件下,栅绝缘层产生钝化,从而能够改善器件的性能。     

电泳法制备ZnO/YBCO异质结及电学性质研究

采用电泳方法及高温煅烧工艺制备ZnO/YBCO异质结,XRD图谱显示ZnO具有c轴方向的择优取向。在SEM的截面图中可观察到ZnO与YBCO结合致密,放大500倍的表面形貌图呈现织构(textured)的微结构特征,放大5000倍的表面形貌图中可观察微米量级的六方晶粒。通过对ZnO/YBCO异质结的电学性质进行测试,结果显示整流特性。     

水热法制备In2O3/ZnO异质结及其高的光催化性能

采用简单的两步水热法合成了不同In₂O₃质量比的In₂O₃/ZnO异质结复合材料．通过X射线衍射仪(XRD)、紫外-可见分光光度计(UV-vis)和扫描电子显微镜(SEM)对复合材料的结构、形貌和性能进行了表征．同时还使用UV-vis分光光度计测试了异质结降解罗丹明B(RhB)的光催化活性．实验结果表明,与纯ZnO和In₂O₃相比,In₂O₃的引入将ZnO的吸收光谱扩展到可见光区域,从而提高了其光生电子和空穴的分离．此外,In₂O₃/ZnO异质结在可见光照射对RhB具有较高的光催化活性．5 wt%-In₂O₃/ZnO异质结对RhB的降解率为84.3%,且具有良好的光催化稳定性．In₂O₃/ZnO异质结复合材料在有机染料废水的降解中有更广阔的应用前景．     

磁控溅射法制备ZnO/YBCO异质结及电学特性

利用磁控溅射技术在YBCO上沉积ZnO薄膜,获得ZnO/YBCO异质结.测量其不同温度下的电学性质,样品显示良好的整流特性,并且随着温度的升高,ZnO/YBCO异质结电流逐渐增大.     

半透明Cu2O/ZnO异质结的制备及其光电性能研究

为研究具有更好材料稳定性的半透明薄膜太阳能电池,本文采用直流磁控溅射技术沉积氧化亚铜(Cu_2O)薄膜和氧化锌(ZnO)薄膜,制备了Cu_2O/ZnO异质结.使用扫描电镜、X射线衍射仪、拉曼光谱仪、薄膜测定系统和太阳能模拟器,研究在不同氩/氧气体流量比的条件下制备的Cu_2O层对异质结的材料特性、光学特性及光电特性的影响.研究结果表明:在一定氩/氧气体流量比范围内制备的Cu_2O/ZnO异质结,在AM1.5的标准模拟太阳光的照射下具有一定的光电转换能力,可作为半透明太阳能电池的换能单元.     

Interface defects in GaN/sapphire studied using Rutherford backscattering spectroscopy and channeling

GaN on sapphire was grown by MOCVD technique. Rutherford backscattering spectra together with channeling along [0 0 0 1] axis were recorded to study the defects at the interface. Detailed calculation shows that the defects at GaN/sapphire interface are due to dislocations which are distributed into the whole thickness of the film and are mainly aligned on the growth direction.     

Depth Dependence of Tetragonal Distortion of a ZnO/Mg0.1Zn0.90/ZnO Heterostructure Studied by Rutherford Backscattering/Channeling

Rutherford backscattering and channeling are used to characterize the structure of a ZnO/Mg0.1Zn0.90/ZnO heterostructare grown on a sapphire （0001） substrate by rf plasma-assisted molecular beam epitaxy. The results show that the Mg0.1Zn0.90 layer has the same hexagonal wurtzite structure as the underlying ZnO layer, and the heterostructure has a good crystalline quality with xmin = 5%, which is the ratio of the backscattering yields of aligned and random spectra in the near-surface region. Using the channeling angular scan around an off-normal （1213） axis in the {1010} plane of both ZnO and MgZnO layer, the tetragonal distortion εT, which is caused by the elastic strain in the epilayer, is determined. The depth dependence of εT is obtained by using this technique. It can clearly be seen that the elastic strain rapidly decreases with the increase in thickness of the ZnO film in the early growth stage and becomes slightly larger in the region of the Mg0.1Zn0.9O layer.     

Tetragonal distortion of InAsPSb film grown on InAs substrate studied by Rutherford backscattering/channeling and synchrotron X-ray diffraction

Rutherford backscattering/channeling spectrometry and synchrotron X-ray diffraction are employed to characterize the structural properties of the InAsPSb epilayer grown on the InAs substrate. The results indicate that a 975-nm thick InAs_0.668P_0.219Sb_0.113 layer has a quite good crystalline quality (χ_min=6.1%). The channeling angular scan around an off-normal 〈1 1 1〉 axis in the (0 1? 1) plane of the sample is used to determine the tetragonal distortion e_T, which is caused by elastic strain in the layer. The results show that the InAsPSb layer is subjected to an elastic strain at the interfacial layer, and the strain decreases gradually moving towards the near-surface layer. It is expected that an epitaxial InAsPSb layer with the thickness of around 1700 nm will be fully relaxed (e_T=0). The magnitude difference of e_T deduced from angular scans and X-ray diffraction implies some structure (like dislocations) may play a role.     

Study of depth-dependent tetragonal distortion of quaternary AlInGaN epilayer by Rutherford backscattering/channeling

A 240-nm thick Al_0.4In_0.02Ga_0.58N layer is grown by metal organic chemical vapour deposition, with an over 1-μ m thick GaN layer used as a buffer layer on a substrate of sapphire (0001). Rutherford backscattering and channeling are used to characterize the microstructure of AlInGaN. The results show a good crystalline quality of AlInGaN (χ_min=1.5%) with GaN buffer layer. The channeling angular scan around an off-normal <12^{-13> axis in the {101-0} plane of the AlInGaN layer is used to determine tetragonal distortion e_T, which is caused by the elastic strain in the AlInGaN. The resulting AlInGaN is subjected to an elastic strain at interfacial layer, and the strain decreases gradually towards the near-surface layer. It is expected that an epitaxial AlInGaN thin film with a thickness of 850 nm will be fully relaxed (e_T = 0).}     

Evidence for barrier-to-well injection of carriers in high quality ZnO/Zn0.9Mg0.1O multiple quantum wells grown on (111) Si

High quality ZnO/Zn_0.9Mg_0.1O multiple quantum wells were grown on (111) Si employing epitaxial Lu₂O₃ buffer layer and a thin ZnO nucleation layer. The linewidth of the low temperature ZnO well emission is only 17 meV. The effective recombination lifetime of emission from ZnO wells is 183 ps. Temperature-dependent photoluminescence is investigated to reveal the behavior of the carriers in the multiple quantum wells. Evidence for the barrier-to-well injection is indicated from the thermal quenching of both the barrier and well emissions. Carrier localization and thermal delocalization are observed in ZnMgO cap/barriers. The depth of the local potential well is determined to be ∼7 meV$\sim 7\text{meV}$.     

Study of depth-dependent tetragonal distortion of quaternary AIInGaN epilayer by Rutherford backscattering/channeling

<正>A 240-nm thick Al_0.4In_0.02Ga_0.58N layer is grown by metal organic chemical vapour deposition,with an over 1-μm thick GaN layer used as a buffer layer on a substrate of sapphire（0001）.Rutherford backscattering and channeling are used to characterize the microstructure of AlInGaN.The results show a good crystalline quality of AlInGaN(x_min= 1.5%) with GaN buffer layer.The channeling angular scan around an off-normal（1213） axis in the {1010} plane of the AlInGaN layer is used to determine tetragonal distortion e_T,which is caused by the elastic strain in the AlInGaN.The resulting AlInGaN is subjected to an elastic strain at interfacial layer,and the strain decreases gradually towards the near-surface layer.It is expected that an epitaxial AlInGaN thin film with a thickness of 850 nm will be fully relaxed （e_T=0）.     

Depth Dependence of Tetragonal Distortion of a ZnO/Mg0.1Zn0.9O/ZnO Heterostructure Studied by Rutherford Backscattering/Channeling

Rutherford backscattering and channeling are used to characterize the structure of a ZnO/Mg_0.1Zn_0.9O/ZnO heterostructure grown on a sapphire (0001) substrate by rf plasma-assisted molecular beam epitaxy. The results show that the Mg_0.1Zn_0.9O layer has the same hexagonal wurtzite structure as the underlying ZnO layer, and the heterostructure has a good crystalline quality with χ_min =5%, which is the ratio of the backscattering yields of aligned and random spectra in the near-surface region. Using the channeling angular scan around an off-normal <12^-13> axis in the {101^-0} plane of both ZnO and MgZnO layer, the tetragonal distortion e_T, which is caused by the elastic strain in the epilayer, is determined. The depth dependence of e_T is obtained by using this technique. It can clearly be seen that the elastic strain rapidly decreases with the increase in thickness of the ZnO film in the early growth stage and becomes slightly larger in the region of the Mg_0.1Zn_0.9O layer.