In0.52Al0.48As/InP的正向和反向异质结在带隙附近的不同光谱现象
Different spectral features near the energy bandgaps of normal and inverse heterostructures of In0.52Al0.48As/InP
吴洋 1胡晓 1刘博文 2顾溢 2查访星1
作者信息
- 1. 上海大学物理系,上海 200444
- 2. 中国科学院上海技术物理研究所,上海 200083
- 折叠
摘要
应用光电导谱(PC)和光致发光谱(PL)研究了由分子束外延在InP(100)衬底上生长In0.52Al0.48As获得的两种异质结外延结构,分别是在InP衬底上生长InAlAs形成的正向异质结样品(样品A:In0.52Al0.48As/InP)和InAlAs层继续生长InP形成的上层为反向异质结的双异质结样品(样品B:InP/In0.52Al0.48As/InP).PL和PC实验采用光从表面入射激发的测量构型,样品测量温度为 77 K.样品A的PC谱显示,在激发光能量大于表面In0.52Al0.48As层的带隙时出现了电导陡降的反常变化,还在 916 nm波长处呈现一小的电导峰结构.PL谱对应此波长位置则出现很强的发光峰.样品B则未观察到上述光谱特征,该差异可从两类异质结不同的界面电子结构获得解释.
Abstract
Photoconductivity(PC)spectroscopy and photoluminescence(PL)spectroscopy were used to characterize two heterostructure configurations of InAlAs/InP grown by molecular beam epitaxy(MBE)on the InP(100)substrate.The sample A is the type called normal heterostructure,which has an In0.52Al0.48As layer grown on InP,while sample B is called the inverse type formed by an InP cap layer on In0.52Al0.48As.The front excitation was employed in both PC experiment and PL experiment and the measurements were conducted at 77 K.The PC spectrum of sample A shows an abnormal step-like drop when the photon energy is larger than the energy band gap of In0.52Al0.48As.The phenomenon implies that the conductance of sample is a multilayer effect including the contribution of interfacial two-dimensional electron gas(2DEG).Moreover,a conductance peak is observed at 916 nm below the bandgap of InP.Accordingly,an intense luminescent peak at the wavelength manifests in the PL spectrum.The origin of the 916 nm peak is attributed to the recombination of 2DEG electrons with the valence band holes excited near the interface.However,the spectral feature of the above energy does not exist in both PC and PL spectra of sample B.This difference may be explained by the different interface electronic structures of the inverse interface.For the latter case,considering that a graded variation in In-As-P composition is related to the inverse interface of InP/InAlAs,the band bending effect should be weak.In such a case,the bound energy of 2DEG in the interface potential well is raised closer to the conductance band of the bulk.Consequently,the recombination energy of 2DEG at the inverse interface with the holes in the valence band is close to the band-to-band transition of InP bulk and the luminescence is difficult to be distinguished from that of bulk InP.The work also demonstrates that the comparative study with both PC technique and PL technique is helpful to provide a full insight into the interface electronic property.
关键词
半导体光谱/半导体界面/光电导/光致发光Key words
semiconductor spectroscopy/semiconductor interface/photoconductance/photoluminescence引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据