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

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 100 W showed the lowest resistivity of 3.8×10^-4 Ω cm and highest visible transmittance of 90.19%. The deposition rate and optical bandgap of ITO films were varied from 20 to 100 nm/min and from 3.68 to 3.77 eV for RF power from 50 to 250 W, 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 100 W. The HIT solar cells deposited at RF power of 100 W also exhibited higher carrier lifetime and implied voltage.