Comparison of C doping technique between SiC and C targets for high-photoresponsivity BaSi2 films by radio-frequency sputtering

High-photoresponsivity BaSi2 films is of great importance for solar cell applications. The photoresponsivity was enhanced greatly in C-doped BaSi2 films formed by sputtering BaSi2 and SiC or C targets. The shift of Raman peak and optical absorption edge with increasing C concentration (n(C)) showed that more C atoms were incorporated in BaSi2 films when the SiC target was sputtered. When n(C) was 6 x 10(20) cm(-3) by the SiC target, the photoresponsivity approached 2 A W-1 under a bias voltage of 0.1 V between the top and bottom electrodes. This is the highest value ever reported for BaSi2 films.