Effect of CuIn1−xAlxSe2 (CIAS) thin film thickness and diode annealing temperature on Al/p-CIAS Schottky diode

Al/p-CIAS Schottky diodes were fabricated by depositing aluminium (Al) on different flash evaporated copper–indium–aluminium–diselenide (CIAS) films of varying thickness. Further, all diodes were annealed at 573 K for an hour. The influence of p-CIAS film thickness and the thermal annealing of Al/p-CIAS Schottky diode were investigated by observing current–voltage (I–V) and capacitance–voltage (C–V) characteristics at room temperature. Various diode parameters, such as ideality factor (η), barrier height (ϕbo) and series resistance (Rs) were calculated using Cheung’s and Norde methods. ϕbo found to increase with annealing as well as with increase in the film thickness. However, the value of η and Rs decreases with annealing and CIAS thickness. The effective density of states (Nv), acceptor density of states (NA) and barrier height have been calculated from C–V measurements. Values obtained from CV analysis were well matched with I–V results. The value of Nv decreases and the value of NA increases with the increase in the film thickness. Using I–V and C–V parameters, energy band gap for the prepared Al/p-CIAS diodes has been reconstructed.