RESUMO
ZnO:Al/n-ZnSe/p-CdTe anisotype heterostructures with diode properties were fabricated by the high-frequency magnetron deposition of ZnO:Al and n-ZnSe thin films onto the surface of crystalline p-CdTe. The flow of currents limited by the space charge at forward voltages up to 0.45 V and tunneling currents at V > 0.45 V was established. A change in these current flow mechanisms was observed at reverse voltages V = -0.6 V. The main part of the energy barrier qÏk = 1 eV of the ZnO:Al/n-ZnSe/p-CdTe heterostructure was formed in the p-CdTe substrate, which was established from studies of capacitance-voltage (C-V) characteristics. A model of the energy diagram of the heterostructure is proposed.
RESUMO
Cu-Sn-S (CTS) thin films were deposited onto bare and molybdenum (Mo) coated glass substrates by means of the spray pyrolysis technique under different conditions. The CTS thin films obtained are shown, by means of Raman spectroscopy, to consist of two main phases: Cu2SnS3 and Cu3SnS4 as well as of the secondary phase of Cu2-xS. The electrical conductivity of the spray-deposited p-type CTS thin films under investigation is determined by two shallow acceptor levels: Ev+0.07 eV at T<334 K and Ev+0.1 eV at T>334 K. The material of the CTS thin films was established to be a direct-band semiconductor with the bandgap Eg=1.89 eV. The SEM and x-ray energy dispersive analysis show the surface and cross section of the CTS thin film deposited onto molybdenum-coated glass ceramics substrate with the actual atomic ratios of Cu:Sn:S being 2.9:1:2.64, which is in good agreement with the Raman spectra. Also, a small content of residual Cl atoms was found in the CTS thin films under investigation as the by-product of the pyrolytic reactions.
