Surface photovoltage spectroscopy of minority carrier diffusion lengths in undoped and Si‐doped GaN epitaxial films
Surface photovoltage spectroscopy of minority carrier diffusion lengths in undoped and Si‐doped GaN epitaxial films
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未掺杂和硅掺杂 GaN 外延膜中少数载流子扩散长度的表面光电压光谱
DOI：
10.1002/pssc.200461332
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
L. Robins
中科院分区：
文献类型：
--
作者：
Seong;J. Kopanski;youn;L. Robins
采用金属-有机化学气相沉积方法在蓝宝石衬底上生长了未掺杂和掺硅的GaN外延膜。用变角椭圆偏振光谱仪(VASE)和表面光电压谱(SPV)测量了薄膜中的少子扩散长度。反射率(R)和吸收系数(α)都可以由花瓶测量得到。在室温下的SPV谱中，两种薄膜都观察到了阈值为3.42 eV的强跃迁，而只有未掺杂的GaN有激子相关的吸收。测得未掺杂GaN的少子扩散长度约为200 nm，掺Si GaN的少子扩散长度约为20 nm。此外，在未掺杂的GaN中发现了1/α范围内的大发散，这归因于高的表面势垒能。(2015Wiley-VCH Verlag GmbH&Co.KGaA，Weinheim)
Undoped- and Si-doped GaN epitaxial films were grown on sapphire substrates by metal-organic chemical vapor deposition. Variable angle spectroscopic ellipsometry (VASE) and surface photovoltage (SPV) spectroscopy were used to determine the minority carrier diffusion lengths in the films. Both the reflectivity (R) and absorption coefficient (α) could be calculated from the VASE measurements. In the SPV spectra at room temperature, a strong transition with a threshold at 3.42 eV was observed in both films, while an exciton-related absorption was observed only in the undoped GaN. The minority carrier diffusion lengths were measured to be about 200 nm for the undoped GaN and about 20 nm for the Si-doped GaN. Moreover, a large divergence in the range of 1/α in the undoped GaN was found and attributed to a high surface barrier energy. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)