Arai Shinya, Ozaki Shunji, Adachi Sadao
Graduate School of Engineering, Gunma University, Kiryu-shi, Gunma 376-8515, Japan.
Appl Opt. 2010 Feb 10;49(5):829-37. doi: 10.1364/AO.49.000829.
The optical properties of AgGaTe(2) chalcopyrite semiconductor are studied by optical absorption, spectroscopic ellipsometry (SE), and thermoreflectance (TR) spectroscopy. Optical absorption spectra suggest that AgGaTe(2) is a direct-gap semiconductor having a bandgap of approximately 1.2 eV at T=300 K. The pseudodielectric-function spectra of AgGaTe(2) are determined by SE in the range between E=1.2 and 5.2 eV for both states of polarization. These spectra reveal distinct structures at energies of the critical points in the Brillouin zone. The TR spectra are also measured in the E=1.0-5.3 eV ranges at T=20 K-300 K. The spin-orbit and crystal-field splitting parameters of AgGaTe(2) are determined to be Delta(so)=0.70 eV and Delta(cr)=-0.23 eV, respectively.
通过光吸收、光谱椭偏仪（SE）和热反射（TR）光谱对AgGaTe₂黄铜矿半导体的光学性质进行了研究。光吸收光谱表明，AgGaTe₂是一种直接带隙半导体，在T = 300 K时带隙约为1.2 eV。通过SE确定了AgGaTe₂在E = 1.2至5.2 eV范围内两种偏振态的伪介电函数光谱。这些光谱揭示了布里渊区临界点能量处的明显结构。还在T = 20 K - 300 K、E = 1.0 - 5.3 eV范围内测量了TR光谱。确定AgGaTe₂的自旋轨道和晶体场分裂参数分别为Δ(so)=0.70 eV和Δ(cr)= -0.23 eV。
