Effect of heat treatment in sulfur on structural, optical and electrical properties of thermally evaporated In2S3 thin films

Abstract

Crystallinity, optical band gap, resistivity and photoresponse of thermally evaporated In 2 S 3 thin films deposited at a temperature of 350 • C and further annealed in sulfur vapour at different temperature range of 200-300 • C is investigated. It is observed that with an increase of annealing temperature, predominantly β-In 2 S 3 phase is formed and the optical band gap for indirect allowed transitions increases from 1.6 eV to 2.0 eV and for direct allowed transitions from 2.3 eV to 2.7 eV. The electrophysical properties indicate that the activation mechanism of conductivity with an activation energy in the range of 0.5-0.73 eV, which is typical for the presence of indium vacancies in the β-In 2 S 3 crystal structure and for the replacement of sulfur by oxygen atoms. It is also noted that sulfur annealing at temperatures of 250-300 • C leads to an increase in the conductivity and photosensitivity of films, which is suitable for photovoltaic applications.

Effect of Post-thermal Annealing on the Structural, Morphological, and Optical Properties of RF-sputtered In2S3 Thin Films

“…From Figure 7(c) and 7(d), it was identified that the direct energy band gaps of the films were found as 2.32, 2.52 and 2.56 eV and the indirect energy band gaps of the films were found as 2.08, 2.24 and 2.36 eV, for the samples IS, IS-350 and IS-450, respectively. The observed band gap values were found to be in concordance with the reported band gap values for In2S3 films in previous studies [25,[50][51][52]. Interestingly, it was found that the high temperature treated films had higher Eg than as-deposited films.…”

The Synthesis and the effect of Cu on optoelectronic qualities of β-In2S3 as a window layer for CIGS thin film solar cells

“…In recent years, among the fierce research focus to finding the best energyefficiency compromise among next-generation solar cells, Perovskite Solar Cells (PSCs) have emerged as one of the most prominent candidates [12]. Moreover, the use of In2S3 as an electron transport layer (ETL) and photosensitizer in (PSCs) has gained much attention in the field of solar energy research [13]. These solar cells are made of a superposition of CuInSe2, Cu(In, GA)Se2 and CuInS2 compounds characterized by a high-efficiency insulating layer [14].…”

On the Stability of Potential Photovoltaic Absorber In5S4

“…However, until now, many studies still use the In 5 S 4 crystal structure reported by Wadsten as a reference. − Moreover, recently, independent works have reported the synthesis of In 5 S 4 without any Sn inclusion: Von Klopmann et al found that sulfurization of elemental In film at ∼250 °C leads to the formation of cubic In 5 S 4 and then decomposes to InS, in which In 5 S 4 is verified by XRD peaks of (222) and (421). Sundaramoorthy et al reported potential In 5 S 4 phase in sulfurization of Cu/In layers.…”

“…Sundaramoorthy et al reported potential In 5 S 4 phase in sulfurization of Cu/In layers. Using vacuum thermal evaporation of In 2 S 3 powder under sulfur vapor, Tivanov et al obtained cubic modification of In 5 S 4 through XRD peaks of (221), (222), (023), (611), (026), and (145). Bayón and Herrero found that In 5 S 4 can form when low concentrations of thioacetamide (sulfur source) and acetic acid (AcOH) are used in InCl 3 solution via chemical bath deposition.…”