Comparison of AZO, GZO, and AGZO Thin Films TCOs Applied for a-Si Solar Cells

This study prepared aluminum and gallium co-doped zinc oxide (AGZO) thin films using pulsed direct current magnetron sputtering, and studied the electrical properties, transmittance, effects of texturing, and applicability as the front contact for a-Si:H solar cells. Textured ZnO:Al (AZO) and ZnO:Ga (GZO) thin films were also compared with AGZO thin film to evaluate their performance as front contacts. Experimental results show that AGZO films with the highest figure of merit phi TC value (24.64 x 10(-3) Omega(-1)) were obtained at Al and Ga doping concentrations of 0.54 wt% and 1.165 wt%, respectively. The textured AGZO films used as the front contact in a-Si:H solar cells achieved the following results: V-OC = 0.77 V, JSC = 16.5 mA/cm(2), FF = 59%, and conversion efficiency of 7.53%. AZO and GZO films have better electrical properties than AGZO film; however, AGZO film has superior transmittance in the near-infrared (NIR) region and higher JSC, conversion efficiency and external quantum efficiency (EQE) than AZO and GZO films under a similar haze value. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.108206jes] All rights reserved.