Novel back-contact back-junction SiGe (BC-BJ SiGe) solar cell for improved power conversion efficiency

In this paper, a SiGe based Back-Contact Back-Junction (BC-BJ) device structure called BC-BJ SiGe solar cell has been proposed. Photo reflection is significantly reduced in UV/Visible spectrum region in case of SiC/Si3N4/SiO2 passivated BC-BJ SiGe solar cell. Result, indicates that presence of SiC play an important role in photoelectric conversion. Ray tracing and finite difference time domain (FDTD) algorithms are used to simulate optoelectronics characteristics of the device. Simulation achieves the barrier height of 0.8 eV for holes at the interface which results in a higher field. The lower interface recombination rate of the order of 10(17) cm(-3) s(-1) has been obtained. The device shows improved photovoltaic parameters. External quantum efficiency > 84 % in the spectrum range of 450-700 nm wavelength and more than 80 % in the range of 350-700 nm wavelength is obtained. Further, we obtained the fill-factor (FF) and power conversion efficiency (PCE), 79 %, 17.8 % and 79 %, 14.8 %, using FDTD and ray tracing methods, respectively. All the simulations have been done using atlas and devedit device simulator.