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 ϕ TC value (24.64 × 10 −3 Ω −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, J SC = 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 J SC , conversion efficiency and external quantum efficiency (EQE) than AZO and GZO films under a similar haze value.