The fabrication of the novel semiconducting material for solar cells which does not use a rare metal

采用垂直布里奇曼法生长了四元半导体Cu_2ZnSnSe_4和Cu_2ZnSnS_4晶体。光吸收测量表明，Cu 2 ZnSnSe 4和Cu 2 ZnSnS 4都是直接带隙半导体，并且在10 K下分别具有1.12和1.48 eV的带隙能量。的热反射光谱揭示不同的结构在E0-E6临界点（CP）的能量。从第一原理能带结构计算，这些CP的被分配到特定点的布里渊区。

The quaternary semiconductor Cu2ZnSnSe4 and Cu2ZnSnS4 crystals were grown by the vertical Bridgman method. Optical absorption measurements indicate that both Cu2ZnSnSe4 and Cu2ZnSnS4 are direct-gap semiconductors, and having the band gap energies of 1.12 and 1.48 eV at 10 K, respectively. The thermoreflectance spectra reveal distinct structures at energies of the E0-E6 critical points (CP's). From the first-principle band-structure calculations, these CP's are assigned to specific points in the Brillouin zone.