Mechanisms of carrier transport in CdTe polycrystalline films

Cadmium telluride (CdTe) polycrystalline films grown on glass ceramic substrates by a modified close-spaced vapor transport technique have been investigated.The as-grown films have columnar structure with the average grain sizes about 10 m.The in-plain direct current conductivity as a function of temperature and electric field has been investigated.The percolation conductivity is shown to be dominant at low temperatures (T < 250 K).At room temperature, the dominant transport mechanism is an activated process such as thermionic emission.The carrier transport across barriers is influenced by traps in the surface barrier regions.The non-annealed films exhibited stable electrical parameters and high photosensitivity during five-year storage under laboratory conditions.