Increase of free carrier lifetime in nonpolar a-plane GaN grown by epitaxial lateral overgrowth
Increase of free carrier lifetime in nonpolar a-plane GaN grown by epitaxial lateral overgrowth
复制标题
通过外延横向过度生长生长的非极性 a 面 GaN 中自由载流子寿命的增加
DOI：
10.1063/1.1777409
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
M. Khan
中科院分区：
文献类型：
--
作者：
S. Juršėnas;E. Kuokštis;S. Miasojedovas;G. Kurilčik;A. Žukauskas;C. Chen;J. Yang;V. Adivarahan;M. Khan
利用强光激发下的时间分辨光致发光技术研究了外延a面GaN和完全结合外延横向过生长(ELOG)a面GaN薄膜中的载流子复合动力学。并与在类似条件下生长的常规c平面GaN薄膜进行了比较。在a平面GaN外延层中，电子空穴等离子体自发发光的总效率比c平面GaN薄膜降低了20倍，而发光衰减时间从τLU=42缩短到τLU⩽10ps。同时，与a平面GaN薄膜相比，ELOGa平面样品的总发射效率显著提高(超过两个数量级)，衰减时间延长至τLU=430ps。这证实了非平衡载流子的非辐射复合速率的显著降低。在非辐射深能级跃迁饱和的情况下，得到了τ的室温自由载流子寿命=910ps。
Carrier recombination dynamics in epitaxial a-plane GaN and fully coalesced epitaxial laterally overgrown (ELOG) a-plane GaN films has been studied by means of time-resolved photoluminescence under high photoexcitation. The results were compared with conventional c-plane GaN films grown under similar conditions. In a-plane GaN epilayers, the total efficiency of electron-hole plasma spontaneous luminescence decreases 20 times, whereas the luminescence decay time reduces from τLU=42 to τLU⩽10ps in comparison with c-plane GaN films. Meanwhile, an essential increase in total emission efficiency (by more than two orders of magnitude) and an increase of the decay time up to τLU=430ps have been observed for an ELOG a-plane sample in comparison with a-plane GaN films. This confirms a significant reduction of the nonradiative recombination rate for nonequilibrium carriers. Assuming a saturation of the nonradiative deep-level transitions, the room-temperature free-carrier lifetime of τ=910ps for ELOG a-plane GaN sa...