Formation of CuInSe2 thin films by rapid thermal recrystallization

Abstract
Polycrystalline thin‐film CuInSe2 has been formed by rapid thermal processing of vacuum codeposited Cu, In, and Se. Films were fabricated and characterized in three composition regions: Cu‐poor (∼20 at. % Cu), stoichiometric (25 at. %), and Cu‐rich (∼28 at. %). Characterization results are presented including x‐ray diffraction analysis, electron probe for microanalysis, scanning electron microscopy, and optical reflection and transmission measurements. Results show that nearly single‐phase material has been formed from codeposited precursors with a post‐deposition annealing time of less than 2 min. The films have optical absorption coefficients in the high 104 cm−1 range with minimum subgap absorption, and an optical band gap of 1.0 eV with smooth morphologies amenable to photovoltaic device fabrication.