Matsumoto, Y. ; Ortega, M. ; Wünsch, F. ; Yu, Z.: Cat-CVD deposited inverted µc-Si:H/c-Si heterojunction solar cell approach. In: 5th International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE 2008)IEEE, 2008. - ISBN 978-1-4244-2499-3, p. 455-459
Abstract:
Catalytic chemical vapor deposition (Cat-CVD), is a new technology to obtain device-quality thin films at low substrate temperatures. In the other hand, the inverted microcrystalline-silicon/crystalline-silicon (μc-Si/c-Si) heterojunction, consists of a solar cell illuminated on the backside, the c-Si part of the hetero-structure. This, structure configuration avoids the light absorption in the heavily-doped emitter (deadlayer) and also eludes the use of transparent conducting oxide (TCO) on the emitter. If the back-surface is properly treated, this structure has the advantage to absorb major part of the solar spectrum. Very thin intrinsic hydrogenated amorphous silicon (i-a-Si) as a buffer-layer, and boron-doped hydrogenated microcrystalline silicon (p-μc-Si) were deposited using Cat- CVD system on crystalline-silicon (c-Si) substrate. Solar cells were fabricated on Czochralsky (CZ)-grown phosphorousdoped c-Si within 0.5 to 1 ohm-cm. The tungsten catalyst temperature (Tfil) 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 (Tsub) of 200 °C. The preliminary IV characteristics under natural solar radiation and corrected to 100mW/cm2 are: Jsc =25.9 mA/cm2; Voc = 480 mV; Jm = 19.24 mA/cm2; Vm = 320 mV; FF = 49.5%. Being an active area efficiency of η= 6.15%.