The Role of Recombination Types in Efficiency Limits of Radial p n junctions based on Si and GaAs

In this study, we analyze and model the recombination mechanisms in radial p-n junction structures composed of Si and GaAs over a temperature range of 250 K to 500 K, in 50 K increments. Using both analytical and computational modeling techniques, we examine the effects of doping concentration, core and shell radius, and external voltage on charge carrier behavior and recombination mechanisms. Our analysis focuses on core radii of 0.5 μm and 1 μm, with a total structure height of 4 μm. The external voltage varies from 0 to 2 V, and the doping levels are set to p = 2×10¹⁶ cm⁻³ and n = 2×10¹⁷ cm⁻³. A comparative analysis of Si and GaAs highlights their respective advantages in semiconductor applications: Si offers cost-effectiveness and stability, while GaAs exhibits superior electron mobility and radiative recombination efficiency. Additionally, we investigate the influence of external voltage on recombination mechanisms, revealing that GaAs has a higher rate of surface and radiative recombination compared to Si, which is more affected by Auger recombination at high doping levels. These findings provide valuable insights into optimizing material selection for high-performance optoelectronic and photovoltaic devices.