Study on the relationships between Raman shifts and temperature range for α-plane GaN using temperature-dependent Raman scattering  

作　　者：王党会 许晟瑞 郝跃 张进成 许天旱 林志宇 周昊 薛晓咏 

机构地区：[1]State Key Laboratory of Fundamental Science on Wide Band-Gap Semiconductor Technology,School of Microelectronics, Xidian University [2]School of Materials Science and Engineering,Xi'an Shiyou University

出　　处：《Chinese Physics B》2013年第2期519-523,共5页中国物理B（英文版）

基　　金：Project supported by the Fundamental Research Funds for the Central Universities,China (Grant No. K50511250002);the National Key Science & Technology Special Project,China (Grant No. 2008ZX01002-002);the Major Program and State Key Program of the National Natural Science Foundation of China (Grant Nos. 60890191 and 60736033);the Science Fund for Youths Scholars (Grant Nos. 61204006)

摘　　要：In this paper,Raman shifts of a-plane GaN layers grown on r-plane sapphire substrates by low-pressure metal-organic chemical vapor deposition（LPMOCVD） are investigated.We compare the crystal qualities and study the relationships between Raman shift and temperature for conventional a-plane GaN epilayer and insertion AlN/AlGaN superlattice layers for a-plane GaN epilayer using temperature-dependent Raman scattering in a temperature range from 83 K to 503 K.The temperature-dependences of GaN phonon modes（A1（TO）,E2（high）,and E1（TO）） and the linewidths of E2（high） phonon peak are studied.The results indicate that there exist two mechanisms between phonon peaks in the whole temperature range,and the relationship can be fitted to the pseudo-Voigt function.From analytic results we find a critical temperature existing in the relationship,which can characterize the anharmonic effects of a-plane GaN in different temperature ranges.In the range of higher temperature,the relationship exhibits an approximately linear behavior,which is consistent with the analyzed results theoretically.In this paper,Raman shifts of a-plane GaN layers grown on r-plane sapphire substrates by low-pressure metal-organic chemical vapor deposition（LPMOCVD） are investigated.We compare the crystal qualities and study the relationships between Raman shift and temperature for conventional a-plane GaN epilayer and insertion AlN/AlGaN superlattice layers for a-plane GaN epilayer using temperature-dependent Raman scattering in a temperature range from 83 K to 503 K.The temperature-dependences of GaN phonon modes（A1（TO）,E2（high）,and E1（TO）） and the linewidths of E2（high） phonon peak are studied.The results indicate that there exist two mechanisms between phonon peaks in the whole temperature range,and the relationship can be fitted to the pseudo-Voigt function.From analytic results we find a critical temperature existing in the relationship,which can characterize the anharmonic effects of a-plane GaN in different temperature ranges.In the range of higher temperature,the relationship exhibits an approximately linear behavior,which is consistent with the analyzed results theoretically.

关 键 词：metal-organic chemical vapor deposition Raman shift crystal quality anharmonic effect 

分 类 号：TN304.055[电子电信—物理电子学]