Characteristics of Zn1−xMgxO:B and its application as transparent conductive oxide layer in Cu(In, Ga)(S, Se)2 solar cells with and without CdS buffer layer. (15th May 2019)

• Record Type: Journal Article
• Authors: Chantana, Jakapan; Kawano, Yu; Nishimura, Takahito; Kato, Takuya; Sugimoto, Hiroki; Minemoto, Takashi
• Is Part Of: Solar energy. Volume 184(2019)
• Page Start: 553
• Page End: 560
• Publication Date: 2019-05-15
• Subjects: Zn1−xMgxO:B -- Zn1−xMgxO:Al -- Cu(In, Ga)(S, Se)2 -- Cd-free thin-film solar cell -- All-dry process -- Metal organic chemical vapor deposition; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2019.04.029
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Zn1− x Mg x O:B (BZMO) was prepared by MOCVD method. Optical and electrical properties of BZMO were investigated. BZMO was applied as TCO of CIGSSe solar cell, where K-treated CIGSSe is absorber. 21.1%-efficient CdS-buffer CIGSSe solar cell was fabricated. 20.2%-efficient Cd-free CIGSSe solar cell was obtained by all-dry process. Abstract: Zn1− x Mg x O:B (BZMO) films were deposited by metal organic chemical vapor deposition (MOCVD). Their optical and electrical properties were investigated for suitability as transparent conductive oxide (TCO) of the Cu(In, Ga)(S, Se)2 (CIGSSe) solar cells. It is disclosed that with the increase in the [Mg]/([Mg] + [Zn]) of the BZMO up to 0.12 the optical band-gap energy (Eg ) is increased to 3.52 eV, and the resistivity is reduced to about 3.1 × 10 −3 Ω·cm owing to the increase in the Hall mobiltity. Moreover, the severe free-carrier absorption in the BZMO film is not observed. The BZMO is consequently appropriate as the TCO layer of the CIGSSe solar cells. The K-treated CIGSSe layers were applied as the absorbers of the solar cells. As a result, the 21.1%-efficient CIGSSe solar cell with a structure of Zn0.88 Mg0.12 O:B/CdS/CIGSSe/Mo/glass is obtained. In addition, the 20.2%-efficient Cd-free CIGSSe solar with a structure of Zn0.88 Mg0.12 O:B/Zn0.80 Mg0.20 O/CIGSSe/Mo/glass, fabricated by all-dry process, is realized with high short-circuit current density (JSC ) of 39.7 mA/cm 2 . The high JSC is attributable to no optical loss in CdS buffer layer, no severe free carrier absorption, and the increased Eg of the BZMO layer.