Parametric investigation for the optimization of ZnSe film formation by low-pressure Se vapour selenization process

• Published in: Vacuum 1999, Vol.55 (1), p.71-76
• Main Authors: Jeyakumar, R., Lakshmikumar, S.T., Rastogi, A.C.
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Selenization; Solar cell materials; Vapor phase epitaxy; growth from vapor phase; ZnSe thin films
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/S0042-207X(99)00125-6

Parametric investigations of the low-pressure Se vapor selenization process for the formation of optically transparent single-phase ZnSe films from bilayer In/Zn precursors are described. An optimized In/Zn bilayer precursor film deposition procedure that eliminates the well-known inhomogeneity problem is described. Selenization reactor pressure controls the reactant availability and the selenization temperature controls the reaction rate. Their effect on the crystalline microstructure and optical band gap reveals that the optimal growth occurs at 350°C and 0.5–1 mbar. X-ray photoelectron spectroscopy data confirm electron charge transfer from Zn to Se leading to ZnSe formation, the absence of multiple valance states for the elements and the formation of single-phase cubic ZnSe. The optical bandgap is 2.68±0.05 eV which decreases marginally with selenization temperature. Electrical resistivity is ≈10 5 Ω cm and the donor activation energy 0.25 eV.