Structure and optical characterization of sulfur incorporated As_(2)Se_(3) crystals

摘要

In this study, structural and optical properties of crystalline sulfur incorporated As_(2)Se_(3) have been characterized using x-ray diffraction and thermoreflectance (TR) measurements at 300 K. The crystalline layer compounds of As_(2)(Se_(1-x)S_(x))_(3) (0 <= x <= 0.4) c-As_(2)(Se_(1-x)S_(x))_(3) were grown by vertical Bridgman method. The lattice parameters were determined by x-ray diffraction measurements. The band structure of c-As_(2)(Se_(1-x)S_(x))_(3) was characterized experimentally by TR measurements in the energy range of 1.25-6 eV. TR spectra of the c-As_(2)(Se_(1-x)S_(x))_(3) (0 <= x <= 0.4) exhibit a multitude of derivativelike features in the vicinity of band edge as well as the higher lying interband transition regions. Interband transition features of the c-As_(2)(Se_(1-x)S_(x))_(3) (0 <= x <= 0.4) are analyzed and the proper transition origins are assigned. Based on the experimental analyses and on the previous band-structure calculations of As_(2)X_(3) (X(velence)S,Se), a probable experimental band scheme near the fundamental edge of As_(2)(Se_(1-x)S_(x))_(3) is then constructed.