Alternate current conductivity in BSb films prepared by PLD technique: Electron transport processes in low-temperature range (10-275 K)

Abstract.

This study is focused on the measurement of alternate current (a.c.) electrical conductivity of BSb films, deposited on fluorine-doped tin oxide (FTO)-coated glass substrates at 673K by the pulsed laser deposition (PLD) technique. The frequency-dependent a.c. conductivity is measured as a function of temperature (10-275K) and frequency (100Hz-100kHz). The transport processes governing the electrical conduction processes in this material are analyzed critically. It is observed from FESEM micrograph that the film is composed of small discrete grain with sizes varying in the range 6-12nm. It is interesting to notice from $\ln\sigma_{\rm ac}$ versus 1000/T plot that there are three distinct zones: i) Semiconductor zone at high temperature from 275 to 150K, ii) Insulator zone at low temperature from 70 to 10K and iii) an abrupt change of the $\ln\sigma_{\rm ac}$ versus 1000/T plot at ∼ 75 indicating MIS transition occurring in this BSb film. We found that the activation energy for the BSb films in the lower-temperature range was quite low ∼ 6 to 41neV, while that in the higher-temperature range was 20 to 50meV.