Highly transparent RF magnetron-sputtered indium tin oxide films for a-Si:H/c-Si heterojunction solar cells amorphous/crystalline silicon

Abstract

We prepared highly transparent magnetron-sputtered indium tin oxide (ITO) films deposited at various RF powers for a-Si:H(p)/c-Si heterojunction solar cell applications. The surface morphology of ITO films improved in terms of an increase in grain size as the RF power increased. Rapid growth of the (400) plane was observed with increasing RF power, while the (222) plane remain unchanged. The ITO film deposited at 100W showed the lowest resistivity of 3.8×10−4Ωcm and highest visible transmittance of 90.19%. The deposition rate and optical bandgap of ITO films were varied from 20 to 100nm/min and from 3.68 to 3.77eV for RF power from 50 to 250W, respectively. Highly transparent ITO films were utilized as the front anti-reflection layer in heterojunctions with intrinsic thin-layer (HIT) solar cells showed the efficiency of 16.3% for RF power of 100W. The HIT solar cells deposited at RF power of 100W also exhibited higher carrier lifetime and implied voltage.