Photovoltaic effects on Franz–Keldysh oscillations in photoreflectance spectra: Application to determination of surface Fermi level and surface recombination velocity in undoped GaAs∕n-type GaAs epitaxial layer structures
Photovoltaic effects on Franz–Keldysh oscillations in photoreflectance spectra: Application to determination of surface Fermi level and surface recombination velocity in undoped GaAs∕n-type GaAs epitaxial layer structures
复制标题
光反射光谱中 Franz-Keldysh 振荡的光伏效应：应用于确定未掺杂 GaAs∕n 型 GaAs 外延层结构中的表面费米能级和表面复合速度
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Nakayama
中科院分区：
文献类型：
--
作者：
H. Takeuchi;Y. Kamo;Y. Yamamoto;T. Oku;M. Totsuka;M. Nakayama
我们证明了在考虑光伏效应的情况下，从光反射光谱中的Franz-Keldysh振荡(FKO)可以同时估计未掺杂的GaAsn型(i-GaAsn型)外延层结构的表面费米能级和表面复合速度。首先，我们对i-GaAs/n-GaAs结构在探针束照射下的表面电场进行了计算研究。表面电场强度对表面费米能级和表面复合速度很敏感。我们发现，这些参数可以从表面电场强度与探测束功率密度的关系来估算。接下来，我们通过分析光伏效应对FKO的影响，从实验上估算了I-GaAs/n-GaAs结构的表面费米能级和表面复合速度。FKO的周期随探测束功率密度的降低而增大。表面费米能级和表面复合速度随温度的变化而变化。
We demonstrate that the surface Fermi level and surface recombination velocity in undoped GaAs∕n-type GaAs (i-GaAs∕n-GaAs) epitaxial layer structures can be simultaneously estimated from Franz–Keldysh oscillations (FKOs) in photoreflectance spectra, taking account of the photovoltaic effects. Initially, we performed computational studies on the surface electric fields in i-GaAs∕n-GaAs structures under the illumination of a probe beam. The surface electric-field strength is sensitive to the surface Fermi level and surface recombination velocity. We have found that these parameters can be evaluated from the dependence of the surface electric-field strength on the probe-beam power density. Next, we estimated experimentally the surface Fermi level and surface recombination velocity in an as-grown i-GaAs∕n-GaAs structure by analyzing the photovoltaic effect on the FKOs. The period of the FKOs increases with a decrease in the probe-beam power density. The surface Fermi level and surface recombination velocity a...