Estimation of band-gap offsets of heterojunctions using J-V-T characteristics

This article presents investigation of use of the current-voltage-temperature characteristics (J-V-T) of an isotype GaAs-AlGaAs (n-N) structure to estimate its conduction band offset (/spl Delta/E/sub c/). The J-V-T characteristics of the heterojunction are calculated using numerical simulation with different assumed values for /spl Delta/E/sub c/. The activation energy (E/sub A/) is then extracted and compared to the assumed value of the offset /spl Delta/E/sub c/. The activation energy is found to be in a direct linear relation with the band offset with a constant that depends on the doping level and applied bias. Using this process, we show that an n-n/sup +/-N GaAs-GaAs-AlGaAs structure has many advantages in the estimation of the offset over the simple structure.