InSe2 박막의 열처리에 따른 전기적 특성에 관한 연구

Abstract

Cadmium sulfide (CdS) is the most widely used cushioning membrane for conventional CIGS solar cells. However, since cadmium (Cd) is a heavy metal which is very harmful to humans and the environment, many alternative materials are being researched to replace it. In the solar cell industry, zinc selenide and indium selenide are the substitutes for cadmium to reduce environmental recycling costs. Indium selenide is a III-VI compound with a direct transition bandgap and has useful properties that can be used in electronic, optoelectronic and solar cells. Indium selenide is suitable as a buffer film for CIGS solar cells because it has a wide range of bandgap control (1.1 ∼ 3.5 eV) and is capable of hetero bonding with CIGS absorption layer. The structural, optical and electrical properties of indium selenide are greatly affected by the deposition process and the post-annealing process. Methods for depositing indium selenide include a co-deposition method, a bridge method, a spray pyrolysis method, an electrodeposition method, a sol-gel method, a chemical vapor deposition method, an organic metal chemical vapor deposition method, and a sputtering method. Sputtering provides high deposition rates and good uniformity without toxic selenium-containing gases (H2Se or Se gas). Simultaneous sputtering can perform simple inline processing. Conditions for replacing the conventional buffer layer in CIGS solar cells require resistivity of ≤ 104 Ωcm, appropriate band gap energy (1.68 eV ≤ Eg ≤ 3.4 eV), and light transmittance of 80% or more. The light transmittance is directly affected by the film thickness, but defects and resistance and the like must be considered. In this experiment, indium selenide thin film and copper electrode were deposited using RF magnetron sputtering, and heat treatment was performed using RTA (Rapid Thermal Annealing). The properties of the thin films were measured using RT66A equipment.