8:20am AS+EM+MS+TF-MoM1 Optical Properties of Bulk GaSe and InSe Single Crystals, S.G. Choi, National Renewable Energy Laboratory,

III-VI compounds generally crystallize in layered-structures characterized by strong covalent interactions within the layers but weak Van der Waals binding between the layers. This unique structural characteristic has made III-VI compounds attractive for their potential applications in nonlinear optics. Among these compounds, in particular, InSe has been considered as a promising candidate for thin film photovoltaic (PV) material owing to its energy bandgap, optical and transport properties. Recently, high-quality epitaxial InSe thin films have been grown on GaSe substrates, and PV device structures containing n-InSe and p-GaSe have been successfully fabricated [1]. In order to design and optimize a high-performance PV device structure, knowledge of optical properties of constituent materials over a wide spectral range is required. However, large discrepancies were found in the properties of GaSe and InSe available in the literature, which have been measured mostly by reflectance methods with the Kramers-Kroni