Comparison study of ZnO-based quaternary TCO materials for photovoltaic application

• Published in: Journal of alloys and compounds Vol. 793; pp. 499 - 504
• Main Authors: Jang, Jun Sung, Kim, Jihun, Ghorpade, Uma, Shin, Hyeong Ho, Gang, Myeng Gil, Park, Sang Deok, Kim, Hyeong-Jin, Lee, Dong Seon, Kim, Jin Hyeok
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-07-2019; Elsevier BV
• Subjects: Carrier density; Circuits; Electrical properties; Electronic properties; Energy conversion efficiency; Energy gap; Flat panel displays; Gallium; Glass substrates; Mg- and Al-doped ZnO; Mg- and Ga-doped ZnO; Mg- and In-doped ZnO; Optical properties; Optoelectronic devices; Organic light emitting diodes; Photovoltaic cells; Short circuit currents; Soda-lime glass; Solar cells; Thin film solar cells; Thin films; Transmittance; Wide band gap; Zinc oxide; Mg- and Ga-doped ZnO; Mg- and Al-doped ZnO; Mg- and In-doped ZnO; Thin film solar cells; Wide band gap
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.04.042

ZnO is of great interest for large-area optoelectronic devices, e.g., flat panel displays, light-emitting diodes, transparent semiconductors, and transparent conductive oxides (TCOs) etc., owing to its good optical properties. In the present study, quaternary ZnO thin films are deposited on a soda lime glass substrate using Mg and group III elements, such as Al, Ga, and In, to enhance the optical and electrical properties. The structural, optical, and electrical properties of quaternary ZnO TCO materials are investigated for improved thin film solar cell performance. All of the films show a uniform microstructure without any void and crack and have a transmittance over 75% in the visible region. They possess comparable band gap differences. Especially, as for the optical properties, a Mg and Ga co-doped ZnO, MgGaZnO (MGZO) thin film shows a high optical band gap of 3.87 eV with a transmittance of about 90% in the visible region. In addition, the MGZO thin film shows improved electrical properties with the lowest resistivity of 3.97 × 10−4 Ωcm, higher carrier concentration of 1.11 × 1021cm−3, high mobility of 14.07 cm2V−1s−1 and lower sheet resistance of 7.39Ω/sq. Moreover, a wide band gap of 3.87 eV is obtained for MGZO thin films, and the performance of a Cu2ZnSn(S, Se)4 (CZTSSe) photovoltaic device fabricated with a MGZO TCO layer is improved owing to higher band gap and outstanding electronic properties. The improved short circuit current results in a device with a MGZO thin film with a power conversion efficiency of 8.79%.
•Comparative study of quaternary transparent conducting oxide with Mg and different group III element (Al, Ga, In) was conducted.•Mg and group III elements co-doped ZnO were deposited on SLG by RF magnetron sputtering system.•The MGZO thin films showed resistivity of 3.97 × 10−4 Ωcm and optical band gap energy of 3.87 eV.•CZTSSe thin films solar cells with MGZO TCO layer showed higher efficiency of 8.79%.