A study on the improved growth rate and morphology of chemically deposited ZnS thin film buffer layer for thin film solar cells in acidic medium

• Published in: Solar energy Vol. 85; no. 11; pp. 2903 - 2911
• Main Authors: Shin, Seung Wook, Kang, So Ra, Gurav, K.V., Yun, Jae Ho, Moon, Jong-Ha, Lee, Jeong Yong, Kim, Jin Hyeok
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2011; Elsevier; Pergamon Press Inc
• Subjects: Acidic medium; Applied sciences; Aqueous solutions; Chemical bath deposition; Chemical vapor deposition; Deposition; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Energy; Energy gap; Exact sciences and technology; Field emission; Glass; Growth rate; Less toxic complexing agent; Morphology; Natural energy; Photoelectric conversion; Photovoltaic cells; Photovoltaic conversion; Solar cells. Photoelectrochemical cells; Solar energy; Thin films; Zinc acetate; Zinc sulfides; ZnS thin films; ZnS thin films; Less toxic complexing agent; Chemical bath deposition; Growth rate; Acidic medium; Buffer layer; Complexation; Scanning electron microscopy; Multilayer coating; Glass; Field emission; Acetate; X ray diffraction; Zinc; Thin film; Solar cell; Zinc sulfide; Thin film cell; Morphology; Zinc oxide; Aqueous solution; Root mean square value; Electrical characteristic
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2011.08.030

► Growth and characterization of thick ZnS thin films deposited using less complexing agent (HMTA) from acidic solution. ► Structural, chemical, morphological and electrical properties of ZnS thin films were investigated. ► ZnS buffer layer deposited using mixed HMTA and Na
2EDTA as complexing agent for CIGS thin film solar cells.
Zinc sulfide (ZnS) thin films have been prepared by chemical bath deposition method with improving growth rate and morphology using the mixed complexing agents of ethylenediamine tetra-acetate disodium salt (Na
2EDTA) and hexamethylenetetramine (HMTA). The effects of HMTA quantity on the morphological, compositional, optical, structural and electrical properties of ZnS thin films with fixed Na
2EDTA concentration have been investigated. ZnS thin films were deposited on glass substrates using aqueous solutions containing zinc acetate dehydrate and thioacetamide in acidic medium (pH 4). Field emission scanning electron microscopy results show that the morphology of a deposited ZnS thin film using HMTA as a complexing agent is rough. However, very uniform and smooth ZnS thin films are obtained using mixed complexing agents of Na
2EDTA and HMTA. The growth rate and root mean square of ZnS thin films are improved with increasing HMTA quantities. X-ray diffraction patterns show that all the ZnS thin films are grown as a hexagonal structure without secondary phase (ZnO) regardless of HMTA quantity. Optical band gap energy of ZnS thin films deposited using mixed complexing agents increase from 3.75 to 3.87
eV with increasing quantity of HMTA.