Sputtered molybdenum thin films and the application in CIGS solar cells

Abstract

Molybdenum (Mo) thin films are prepared by magnetron sputtering with different discharge powers and working pressures for the application in Cu(In, Ga)Se2 (CIGS) thin film solar cells as back electrodes. Properties of these Mo thin films are systematically investigated. It is found that the dynamic deposition rate increases with the increasing discharge power while decreases with the increasing working pressure. The highest dynamic deposition rate of 15.1nmm/min is achieved for the Mo thin film deposited at the discharge power of 1200W and at the working pressure of 0.15Pa. The achieved lowest resistivity of 3.7×10−5Ωcm is attributed to the large grains in the compact thin film. The discharge power and working pressure have great influence on the sputtered Mo thin films. High efficiency of 12.5% was achieved for the Cu(In, Ga)Se2 (CIGS) thin film solar cells with Mo electrodes prepared at 1200W and low working pressures. By further optimizing material and device properties, the conversion efficiency has reached to 15.2%.