Preparation of TlInSe2 thin films using substrate temperature: Characterization, optical and electrical properties

Abstract

Chalcogenide materials are very applicable materials that have been utilized in different fields of industry such as photovoltaic, fuel cell, battery, and sensor. Here, we report the fabrication, structure, optical, and DC electrical properties of TlInSe2 thin films with different thicknesses (195, 229, and 365 nm). The structural properties have been studied using XRD and AFM. The results showed that the prepared films are polycrystalline in the Tetragonal system and that the crystalline size increases with the increase of the film's thickness. The lattice indices of TlInSe2 and the inter-planar spacing for each diffraction peak have been calculated. The linear and nonlinear optical parameters have been determined using spectrophotometric measurements in the wavelength range of 200–2500 nm. It is found that the direct energy gap (Egd), the indirect energy gap (Egind), and the phonon energy (Eph) are 1.89, 1.61, and 0.025 eV, respectively. The electrical conductivity measurements were also made for TlInSe2 films of different thicknesses and at temperatures in the range of 30–140 °C. The finding results for our fabricated thin films qualify them for employment in optoelectronic applications.