Positive and negative photoconductivity in sprayed β-In2S3 thin films

Abstract

In2S3 indium sulfide thin films were deposited on glass substrates by chemical reactive pulverization in liquid phase at substrate temperature of 300 °C. The layers obtained were characterized by x-ray diffraction (XRD), Raman spectroscopy, spectrophotometry and photoluminescence (PL). In this work, photoconductivity study was conducted using white light source (halogen lamp) and red laser source (λ = 655 nm). This study shows that the photocurrent follows power law with the change of white light irradiance and linear law as function of the bias voltage. The traps energy depths were estimated from photocurrent decay. However, when the bias voltage is shifted to low values, the In2S3 material reveals negative photoconductivity. An interpretation of this behavior was also proposed.