The transition layer in TiB2-GaAs and Au-TiB2-GaAs Schottky contacts

Spectral characteristics of the transverse bulk photovoltage in the TiB2-Ga As and Au-TiB2-GaAs Schottky contacts for starting samples (unannealed) and samples annealed at 400, 600, and 800 degreesC were measured. The concentr ation of the dopant for the n-GaAs substrate was 10(16) cm(-3). It was foun d that the transition layer is formed in the TiB2-GaAs structures owing to the diffusion of boron atoms into the GaAs substrate. Thermal annealing lea ds to an increase in the doping level of the layer. For the Au-TiB2-GaAs st ructure, the transition layer is formed, with the doping level of this laye r being weakly affected by thermal annealing. The spectral position of the bulk-photovoltage peaks indicates that the tails of the density of states a re formed in the band gap of the semiconductor transition layer owing to an increase in the dopant concentration to 10(17)-10(18) cm(-3). (C) 2001 MAI K "Nauka/Interperiodica".