Dynamics of Below—Band—Gap Carrier in Highly Excited GaN
动态下面带隙运营商在高激发氮化镓作者机构：DepartmentofPhysicsTheHongKongUniveristyofScienceandTechnologyClearWaterBaykowloonHongKong StateKeyLaboratoryofsiliconMaterialsZhejiangUniversityHangzhou310027 DepartmentofPhysicsKansasStateUniversityManhattanKansas66506-2601USA
出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)
年 卷 期：2003年第20卷第5期
页 面：749-752页
核心收录：
学科分类：080903[工学-微电子学与固体电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 08[工学] 070205[理学-凝聚态物理] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0704[理学-天文学] 0702[理学-物理学]
主 题：GaN 氮化镓 半导体 反射率 动力学 光谱分析 性质 热声效应 隧道效应
摘 要：Femtosecond time-resolved reflectivity was used to investigate below-band-gap (3.1 eV) carrier dynamics in a nominally undoped GaN epilayer under high excitation. A 2.5-ps rising process can be observed in the transient trace. This shot rising time results from the hot phonon effects which can cause a delayed energy relaxation of the initial photocarriers toward the band edge. From the density dependence of the carrier dynamics, the Mott density was estimated to be 1.51-1.56 x 1019cm-3. Below the Mott density, the initial probed carrier dynamics was explained to the effect of acoustic phonon-assisted tunneling for localized states, where a significant excitation density dependence of the tunneling probability was observed due to the optically-induced bandtail extension to lower energies. Above the Mott density, the measured carrier dynamics reflected the relaxation of an electron-hole plasma, in which a distinct fast decay component of 2.3 ps was observed due to the onset of nonlinear relaxation processes such Auger recombination.
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