We investigated the properties of hydrogenated amorphous silicon oxide (a-Si 1Àx O x :H) deposited near the phase transition between amorphous and microcrystalline structures. a-Si 1Àx O x :H films were prepared by plasma-enhanced chemical vapor deposition using a gas mixture of silane, hydrogen, and carbon dioxide. The film structure was changed from amorphous to microcrystalline phase by increasing hydrogen dilution. Optical and electrical characterizations revealed that wide-gap a-Si 1Àx O x :H films were deposited under phase transition conditions. We also fabricated a-Si 1Àx O x :H single-junction p-i-n solar cells by varying the hydrogen dilution for the i-layer. The solar cells showed a maximum open circuit voltage of 1.04 V (J sc ¼ 7:92 mA/cm 2 , FF ¼ 0:64, E ff ¼ 5:2%) when the i-layer was deposited under phase transition conditions.

We have deposited p‐type hydrogenated amorphous silicon oxide (p‐a‐Si1‐xOx:H) by 13.56 MHz radio frequency plasma enhanced chemical vapor deposition (RF‐PECVD) using a gas mixture of silane (SiH4), hydrogen (H2), carbon dioxide (CO2) and diborane (B2H6). Optical and electrical characterization showed that high quality wide optical band‐gap (Eopt) p‐a‐Si1‐xOx:H films could be achieved by using low doping concentration and high H2 dilution. We also fabricated a‐Si1‐xOx:H single‐junction p‐i‐n solar cells by using p‐a‐Si1‐xOx:H and intrinsic a‐Si1‐xOx:H as window and absorber layer, respectively. These solar cells exhibited open circuit voltages of over 1.05 V and good short‐circuit currents as well as fill factors (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

No abstract

No abstract

Multi-junction silicon-based thin-film concentrator solar cells are promising candidate to achieve both low-cost and high-efficiency. For the application of silicon-based thin film solar cells to concentrator photovoltaics, it is required to be revealed the light intensity dependence of the performance of silicon-based thin film solar cells. From these reasons, in this study both calculation and experimental studies were conducted with several types of single-junction and multi-junction tandem solar cells. From both simulation and measurement results, we observed that double-and triple-junction solar cells achieve high open-circuit voltage and large logarithmic increment in open-circuit voltage with increasing lightintensities. On the other hand, it became clear that the drop of fill factor is required to be improved for the realization of the multi-junction silicon-based thin-film solar cells with very high efficiency under low concentration ratios of sunlight.