HW-CVD deposited microcrystalline-silicon on crystalline-silicon solar cell with inverted heterojunction structure

p-microcrystalline-silicon/n-crystalline-silicon hetero-junction solar cell has been prepared by means of hot-wire chemical vapor deposition (HW-CVD) technique. The solar cell structure was illuminated on the opposite side of the normally-formed heterojunction. With this inverted structure, the photovoltaic cell has the design potential increasing the light-incident surface texturing and it avoids the use of transparent conducting oxide (TCO). The HW-CVD has employed for the deposition of a very thin intrinsic hydrogenated amorphous silicon (i-a-Si) as a buffer-layer, and boron-doped hydrogenated microcrystalline silicon (p-μc-Si) on crystalline-silicon (c-Si) substrate. Solar cells were fabricated on Czochralsky (CZ)-grown phosphorous-doped c-Si within 0.5 to 1 ohm-cm. The tungsten catalyst temperature (T_fil) was settled to 1600 °C and 1950 °C for i-a-Si and p-μc-Si films, respectively. Silane (SiH₄) and hydrogen (H₂) gases were used and diluted diborane (B₂H₆) for p-doping at the substrate temperatures (T_sub) of 200 °C. The obtained I-V characteristics under simulated solar radiation at 100mW/cm² are: Jsc =26.1 mA/cm²; Voc = 545 mV; Jm = 21.4 mA/cm²; Vm = 410 mV; FF = 61.7%, with total area efficiency of η = 8.8%.