Hot-wire CVD deposited n-type μc-Si films for μc-Si/c-Si heterojunction solar cell applications

Phosphorous-doped microcrystalline silicon (μc-Si) films were prepared using hot-wire chemical vapor deposition (HWCVD). Structural, electrical and optical properties of these thin films were systematically studied as a function of PH3 gas mixture ratio. We report recent results for p-type crystalline silicon-based heterojunction (HJ) solar cells using the HWCVD n-μc-Si film to form an n–p junction. The surface morphology of the crystalline Si substrate after hydrogen treatment was examined using atomic force microscopy. A transfer length method was used to modify the indium–tin–oxide (ITO) deposition parameters in order to reduce front ITO/n-μc-Si contact resistance. In our best solar cell sample (1 cm2) without any buffer layer, the conversion efficiency of 15.1% has been achieved with an open circuit voltage of 0.615 V, fill factor of 0.71 and short circuit current density of 34.6 mA/cm2 under 100 mW/cm2 condition. The spectral response of this cell will also be discussed.