307 resultados para PD(111)
Resumo:
采用AlN插入层技术在Si(111)衬底上实现无微裂GaN MOCVD生长.通过对GaN外延层的a,c轴晶格常数的测量,得到了GaN所受张应力与AlN插入层厚度的变化关系.当AlN厚度在7~13nm范围内,GaN所受张应力最小,甚至变为压应力.因此,GaN微裂得以消除.同时研究了AlN插入层对GaN晶体质量的影响,结果表明,许多性能相比于没有AlN插入层的GaN样品有明显提高.
Resumo:
利用衍衬、SAED、HRTEM对在(111)Si上外延生长的六方GaN进行了观察分析。GaN外延层与缓冲层和基底的取向关系为(0001)_(GaN)∥(0001)_(AlN)∥(111)_(Si),[11(2-bar)0]_(GaN)∥[11(2-bar)0]_(AlN)∥[110]_(Si)。GaN外延层中存在倒反畴。GaN中位错以刃型位错为主。In_(0.1) Ga_(0.9) N/GaN的多重量子阱结构(MQW)具有阻挡穿透位错,降低位错密度的作用。
Resumo:
国家973计划
Resumo:
于2010-11-23批量导入
Resumo:
于2010-11-23批量导入
Resumo:
采用结谱、光荧光等技术对Pd和Zt在GaAs中的光学和电学性质进行了研究.在GaAs:Pd中观测到三个能级,分别位于导带下0.4eV、0.60eV和价带上0.69eV.在GaAs:Zr中也观测到三个能级,分别位于导带下0.43eV和介带上0.32eV和0.55eV.基于深中心所表现出的Poole-Frenkel效应,讨论了一些中心对应的荷电态,对它们的俘获和对光致发光的影响也作了研究,结果表明:Pd和Zr在GaAs中均不是有效的复合中心.
Resumo:
采用质量分离的低能双离子束淀积(IBD)技术,在硅(111)衬底上共淀积,生长了氧化铈外延薄膜。椭圆偏振仪测得,膜厚2000A。俄歇能谱仪测得,外延层内铈、氧分布均匀,具有很好的正化学比。X射线双晶衍射得到明显的氧化铈(111),(222)峰,半高宽≤23''。
Resumo:
4d过渡杂质Mo、Pd在GaAs中分别引入E(0.42eV)、H(0.61eV)和E(0.66eV)、H(0.69eV)等能级。根据过渡杂质Mo和Pd在GaAs中的光电行为, 推测这些杂质在GaAs中不起有效复合中心的作用。图4参3
Resumo:
于2010-11-23批量导入
Resumo:
中科院基金
Resumo:
于2010-11-23批量导入
Resumo:
其它基金
Resumo:
Microstructural and compositional characteristics of GaN films grown on a ZnO-buffered Si(111) wafer
Resumo:
Polycrystalline GaN thin films have been deposited epitaxially on a ZnO-buffered (111)-oriented Si substrate by molecular beam epitaxy. The microstructural and compositional characteristics of the films were studied by analytical transmission electron microscopy (TEM). A SiO2 amorphous layer about 3.5 nm in thickness between the Si/ZnO interface has been identified by means of spatially resolved electron energy loss spectroscopy. Cross-sectional and plan-view TEM investigations reveal (GaN/ZnO/SiO2/Si) layers exhibiting definite a crystallographic relationship: [111](Si)//[111](ZnO)//[0001](GaN) along the epitaxy direction. GaN films are polycrystalline with nanoscale grains (similar to100 nm in size) grown along [0001] direction with about 20degrees between the (1 (1) over bar 00) planes of adjacent grains. A three-dimensional growth mode for the buffer layer and the film is proposed to explain the formation of the as-grown polycrystalline GaN films and the functionality of the buffer layer. (C) 2004 Elsevier Ltd. All rights reserved.