Optical and structural investigation of a-plane GaN layers on r-plane sapphire with nucleation layer optimization  

作　　者：张金风 许晟瑞 张进成 郝跃 

机构地区：[1]School of Microelectronics,Xidian University [2]Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices,Xidian University

出　　处：《Chinese Physics B》2011年第5期409-412,共4页中国物理B（英文版）

基　　金：Project supported by the National Key Science & Technology Major Project of the Ministry of Science and Technology of China(Grant No. 2008ZX01002-002);the Major Program and the Key Program of the National Natural Science Foundation of China(Grant Nos. 60890191 and 60736033)

摘　　要：Nonpolar a-plane GaN epilayers are grown on several r-plane sapphire substrates by metal organic chemical vapour deposition using different nucleation layers： （A） a CaN nucleation layer deposited at low temperature （LT）; （B） an A1N nucleation layer deposited at high temperature; or （C） an LT thin AIN nucleation layer with an AIN layer and an A1N/A1CaN superlattice both subsequently deposited at high temperature. The samples have been characterized by Xray diffraction （XRD）, atomic force microscopy and photoluminescence. The GaN layers grown using nucleation layers B and C show narrower XRD rocking curves than that using nucleation layer A, indicating a reduction in crystal defect density. Furthermore, the GaN layer grown using nucleation layer C exhibits a surface morphology with triangular defect pits eliminated completely. The improved optical property, corresponding to the enhanced crystal quality, is also confirmed by temperature-dependent and excitation power-dependent photoluminescence measurements.Nonpolar a-plane GaN epilayers are grown on several r-plane sapphire substrates by metal organic chemical vapour deposition using different nucleation layers： （A） a CaN nucleation layer deposited at low temperature （LT）; （B） an A1N nucleation layer deposited at high temperature; or （C） an LT thin AIN nucleation layer with an AIN layer and an A1N/A1CaN superlattice both subsequently deposited at high temperature. The samples have been characterized by Xray diffraction （XRD）, atomic force microscopy and photoluminescence. The GaN layers grown using nucleation layers B and C show narrower XRD rocking curves than that using nucleation layer A, indicating a reduction in crystal defect density. Furthermore, the GaN layer grown using nucleation layer C exhibits a surface morphology with triangular defect pits eliminated completely. The improved optical property, corresponding to the enhanced crystal quality, is also confirmed by temperature-dependent and excitation power-dependent photoluminescence measurements.

关 键 词：a-plane GaN metal organic chemical vapour deposition A1N/A1GaN superlattice PHOTOLUMINESCENCE 

分 类 号：O472.3[理学—半导体物理]