Growth and characterization of Sb2Se3 and SnSe2 crystals for photovoltaic applications

Abstract

Tremendous development in crystal growth technology led to the production of good newlinequality samples for the design and fabrication of optoelectronic devices. As naturally available solids exhibit undesirable characteristics, the present research work deals with the artificial synthesis and characterization of defect free binary layered chalcogenide materials newline(LCMs) for photovoltaic (PV) applications. Antimony selenide (Sb2Se3) and tin diselenide newline(SnSe2) have gained special attention in the PV industry due to their eco-friendly, sustainable, and non-hazardous nature as well as the salient features such as moderate melting temperature, p-type conductivity with direct transition, optimum band gap and high newlineabsorption coefficient. Therefore, cost-effective synthesis was implemented to engineer bulk Sb2Se3 and SnSe2 crystals for the enhancement of optoelectronic parameters. Single crystal growth from melt allows the fabrication of large size samples under controlled environment. It gives rise to complexities in maintaining stable temperature for crystallization and newlineachieving chemical homogeneity, if multiple elements are present in the system. The newlinechallenges associated with Bridgman-Stockbarger and Czochralski methods for preparing bulk crystals include irregular heat flow, mechanical movement of furnace or crucible, thermal stress, etc. Moreover, reactivity of the melted material with the ampoule leads to structural irregularities. Hence, horizontal normal freezing (HNF), the facile and inexpensive melt growth technique was employed to explore the suitability of cleaved samples. Most of the vapor phase synthesis methods, especially, the chemical vapor deposition (CVD) deteriorates material quality, which adversely affects the physical properties due to the presence of contamination or foreign elements. But, the physical vapor deposition (PVD) process is favorable as it offers feasible instrumentation and yields stoichiometric specimens with supreme quality and fine-tuned characteristics.