Transparent pentacene-based photoconductor: high photoconductivity effect

In this paper, the fabrication and characterisation of pentacene-based photoconductors using indium tin oxide electrodes obtained by ion beam sputtering are discussed. The photoelectric properties of pentacene under red (632 nm) and ultraviolet (365 nm) illuminations were investigated. We have shown that the photocurrent was dependent on the wavelength, bias voltage and illumination side of the device. Moreover, we have demonstrated with transparent electrodes that the top contact configuration yields better performance compared to the bottom contact configuration. We obtained a maximum photoconductivity gain of approximately 3×10 and a faster dynamic response when the photoconductor with top contact geometry was illuminated with ultraviolet light from the semiconductor side (top illumination), with a photoconductivity estimated at 10 Ω cm.