p型GaAs的远红外波段光学特性

Optical Properties of p-Type GaAs in Far-Infrared Region

砷化镓（GaAs）是太赫兹波段半导体异质结构激光器的重要材料之一，为了获得P型Ga觚材料在远红外波段的光学特性，采用气态源分子束外延（GSMBE）技术在半绝缘GaAs（100）衬底上生长了掺Be的P型GaAs薄膜材料，其载流子浓度从1．54×10^15～1．85×10^19cm^-3。用远红外变换傅里叶光谱仪测量了其远红外反射光谱，并对反射光谱进行了理论模拟和分析，计算得出了不同空穴浓度的P型GaAs在远红外波段的折射率、消光系数和吸收系数。发现在这一波段消光系数和吸收系数均随着载流子浓度的增加而增大，吸收系数最大值可达到4．0×10^4cm^-1。

GaAs is an important material for the fabrication of semiconductor heterostructure lasers working at terahertz frequencies. To study the optical properties of p-type GaAs in far-infrared region, p-type （Be-doped） GaAs with carrier concentrations varied from 1.54 × 10^15 - 1.85 × 10^19 cm^-3 has been epitaxially grown by gas source molecular beam epitaxy （GSMBE） on semi-insulating GaAs （100） substrates. Fourier transform infrared （FTIR） spectrometer is employed to characterize far-infrared reflectance spectra of the p-type GaAs. Simulation of the measured far-infrared reflectance spectra has been performed. And refractive indices, extinction coefficients and absorption coefficients for different carrier concentrations have been determined. It is found that extinction coefficients and absorption coefficients increase with the carrier concentration in far-infrared region, and the maximum of absorption coefficients can reach 4.0 × 10^4 cm^-1.