Heteroepitaxial Growth of CuGaS 2 Layers by Low-Pressure Metalorganic Chemical Vapor Deposition

Publisher Website
Google Scholar
Abstract
Heteroepitaxial growth of CuGaS2 was studied by low-pressure metalorganic chemical vapor deposition using normal-tripropylgallium as a new Ga precursor, combined with cyclopentadienylcoppertriethylphosphine and ditertiarybutylsulfide. Structural and optical properties were characterized in detail. The epilayer showed the c[001]-oriented growth on both GaAs(001) and GaP(001) substrates. The lattice parameter c of the epilayers was smaller than that of the bulk single crystal. Magnitude of the residual lattice strain for CuGaS2/GaP(001) was found to be larger than that for CuGaS2/GaAs(001), even though the lattice mismatch for the former was smaller than that for the latter. The strain is considered to be introduced during cooling after the growth. A photoluminescence peak at 2.493 eV (8 K) was assigned to a free exciton emission, because the peak energy agreed with A-exciton energy obtained from photoreflectance spectra.