摘要
室温下采用背散射几何配置,在近共振条件下测量GaAs1-xNx混晶的喇曼散射谱.由于N原子的引入,导致类GaAs的LO1、TO1声子和类GaN的LO2声子线宽变大,禁戒的TO1声子变为喇曼活性;随着N组分的增加,TO1声子强度增大、LO1声子有红移的趋势、LO2声子有蓝移的趋势,根据它们随N组分x移动的速度推断出样品不存在应变效应.另外还讨论了布里渊区边界声子LA(L)与LO(L)、二级喇曼散射谱声子LO2、LO1+LA1(L)以及2LO1随N组分x增大的变化趋势.
Near-resonant back-scattering Raman studies of GaAs_(1-x)N_x(x=0.1%～1.7%)alloys at room temperature are reported.The Raman spectra exhibits two-mode behavior.With the N incorporation,the full widths at half maximum (FWHM)of GaAs-like LO_1 mode and TO_1 mode are broader than those of the pure GaAs.The forbidden TO_1 mode is activated and its intensity is enhanced with increasing the N content, while the ratio of I_(TO1)/I_(LO1) remains constant.The red-shift of the LO_1 mode is smaller and the blue-shift of the GaN-like LO_2 mode is larger than those reported in previous studies,which indicate that the alloying effect instead of the strain effect exists in the alloys.The trends of LA(L)、LO(L)、LO_2、LO_1+LA_1(L)、2LO_1 phonons with increasing the N composition are also disscussed. These trends are attributed to the breakdown in the zinc blende crystal long-range order.
出处
《厦门大学学报（自然科学版）》
CAS
CSCD
北大核心
2004年第3期326-330,共5页
Journal of Xiamen University：Natural Science
基金
国家自然科学基金(60276002)
福建省自然科学基金(A0110007)资助
