Structural and electrical properties of the Al/p-Cu₂ZnSnS₄ thin film schottky diode

In order to calculate the Schottky barrier parameters and to explain the resulting effects, the conduction mechanisms in a Schottky barrier should be known. In the present study, we investigated the structural and electrical properties of Al/p-Cu₂ZnSnS₄ (CZTS)/Mo thin film Schottky junction. Structural characterization was carried out using X-Ray diffraction and Raman Scattering whereas electrical characterization was performed by using the current–voltage (I–V) characteristics and by recording the AC impedance spectroscopy over a wide range of temperature up to 558 K in the frequency range 5 Hz–13 MHz. The complex impedance plots display one semicircle with equivalent circuit functions as typical parallel RC connected to a serial resistance. The characteristic parameters such as barrier height, ideality factor and series resistance have been calculated from the I–V measurements. At room temperature, this heterostructure has shown non-ideal Schottky behavior with an ideality factor of 1.56 and 0.829 µA as a saturation current. By the impedance spectroscopy technique, we have found that all of the serial resistance R_s and the parallel resistance Rp decrease by increasing temperature whereas the capacitance C₀ increased from 0.76 to 1.07 µF. From the Arrhenius diagram, we estimated activation energy at 0.289 eV which represents the energy difference between the trap level and the valence band.