Capacitance-Voltage Characterization of GaAsBi/GaAs Multiple Quantum Wells Grown by Molecular Beam Epitaxy

Abstract Incorporating Bismuth into Gallium Arsenide (GaAs) presents significant potential as a replacement for GaAs or InGaAs in the middle layer of multi-junction solar cells. This is due to its lower lattice strain, which allows for better manipulation and maximization of the total current collected from photovoltaic cells, ultimately enhancing the total power output. This study presents a systematic study of various p-i-n diode structures of GaAsBi/GaAs multiple quantum well (MQW), grown by using molecular-beam epitaxy (MBE). Capacitive-voltage (C-V) characterizations were conducted on these structures by using a multi-frequency LCR meter to analyze the depletion region and doping profile after growth. Data collected from the C-V profiling revealed that bulk capacitance dominates over other parasitic effects. Additionally, the intrinsic i-region width and doping density were determined by using Poisson equation fitting curve. The diodes exhibited doping densities ranging from 1.5×10 16 cm −3 to 5.5×10 16 cm −3 and their i-region width are consistent with the nominal values declared during growth. In conclusion, this material system diodes with different well width were grown and fabricated, exhibiting conventional III-V semiconductor behavior, making them a competitive alternative for related electronic applications.