Polycrystalline Cu(InGa)Se2 thin-film solar cells with ZnSe buffer layers

• Published in: Japanese Journal of Applied Physics Vol. 34; no. 11; pp. 5949 - 5955
• Main Authors: OHTAKE, Y, KUSHIYA, K, ICHIKAWA, M, YAMADA, A, KONAGAI, M
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese journal of applied physics 1995
• Subjects: Applied sciences; Energy; Exact sciences and technology; Natural energy; Photovoltaic conversion; Solar cells. Photoelectrochemical cells; Solar energy; Copper Indium Gallium Selenides Mixed; Copper Selenides; Atomic layer method; Polycrystal; Experimental study; Thin film; Solar cell; Indium Selenides; Gallium Selenides; Preparation; Zinc Selenides; Microstructure; Electrical characteristic
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.34.5949

A ZnSe buffer layer has been applied as an attractive alternative to a CdS buffer layer in the development of polycrystalline Cu(InGa)Se2 (CIGS) thin-film solar cells, thus eliminating entirely the use of cadmium by employing the ZnO/ZnSe/CIGS structure. Moreover, we propose the use of a new deposition method for ZnSe buffer layers, the atomic-layer deposition (ALD) method. This method is basically the same as an atomic-layer epitaxy method but is applied to polycrystalline materials. Currently the best efficiency of CIGS thin-film solar cells with an about 10-nm-thick ZnSe buffer layer is 11.6 percent. Applying irradiation with a solar simulator under one-sun (AM - 1.5, 100 mW /sq cm) conditions, the efficiency of these cells was improved from about 5 percent to over 11 percent due to increased open-circuit voltage and fill factor with no change in short-circuit current density even after six-hour irradiation. (Author)