Theoretical Study of Spontaneous Emission Spectra in GaAsBi/GaAs Quantum Wells

Abstract

GaAsBi/GaAs heterojunctions have a type II band arrangement, and the band structure energy of GaAs alloys with diluted Bi content provides a wide range for designing effective band gaps. In this paper, we calculate the electronic energy band structure of GaAsBi/GaAs quantum wells (QWs) with different Bi concentrations under the 8-band K · P model. The calculated results show that the Bi concentration has a great influence on the band gap, valence band, conduction band, and other structures of GaAsBi/GaAs QWs. Based on the band structure, we make systematical simulations on the effects of different quantum well widths, different Bi concentrations, different carrier densities, and different temperatures on the spontaneous emission spectra (SES) of GaAsBi/GaAs QWs. We find that the peaks of SES reduce with the increase of temperature and well width of the quantum well structure. The full width at half maximum (FWHM) of SES at 300 K is 0.1 eV, which is much broader than that at 100 K. The increasing Bi concentration is found to give rise to the blue shift of SES. Finally, the carrier concentration in the quantum well is found to be an important factor that can enhance the SES peak values. The findings in this work are helpful in the design of GaAsBi/GaAs-based optoelectronic devices.