Effect of excitation frequency on the performance of amorphous silicon alloy solar cells

We have studied amorphous silicon alloy solar cells made by using a modified-very-high-frequency glow discharge at 75 MHz with a deposition rate of similar to 6 Angstrom/s. The solar cell performance is compared with those made from conventional glow discharge at 13.56 MHz with lower deposition rates. Cells made at similar to 6 Angstrom/s with 75 MHz showed comparable stabilized efficiency to those made at similar to 3 Angstrom/s with 13.56 MHz. The best performance, however, was obtained with similar to 1 Angstrom/s, including a stabilized 9.3% a-Si alloy single-junction cell employing conventional glow discharge technique. Using 75 MHz, we have achieved 11.1% and 10.0% initial active-area efficiencies for a-Si alloy and a-SiGe alloy n i p cells, respectively. An initial efficiency of 11.0% has also been obtained in a dual bandgap double-junction structure.