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 ( ϕ bo ) and series resistance ( R s ) were calculated using Cheung’s and Norde methods. ϕ bo found to increase with annealing as well as with increase in the film thickness. However, the value of η and R s decreases with annealing and CIAS thickness. The effective density of states ( N v ), acceptor density of states ( N A ) 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 N v decreases and the value of N A 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.