RF magnetron sputtered indium tin oxide films with high transmittance and work function for a-Si:H/c-Si heterojunction solar cells

Abstract

The RF magnetron sputtered indium tin oxide (ITO) films were deposited on glass substrates with low resistivity, high transmittance and work function for various oxygen (O2) flow rates. The addition of small O2 contents during the sputtering process increased the Hall mobility of ITO films while carrier concentration was decreased. The work function of ITO films was enhanced from 4.31 to 4.81 eV through the growth of (222) plane having relatively low surface energy. The highly transparent ITO films were employed as front anti-reflection layer in heterojunction with intrinsic thin layer (HIT) solar cells and the best photo-voltage parameters were found to be; Voc = 665 mV, Jsc = 35.1 mA/cm2, FF = 73.2% and η = 17.1% for the O2 flow rate of 0.1 sccm. The high work function ITO films play an important role for barrier height modification in HIT solar cell.