A theoretical comparison of the pressure dependence of the threshold current of phosphorus-, aluminium- and nitrogen-based 1.3 μm lasers

摘要

A comparative study of the three competing laser materials, InGaAsP-InP, AlGaInAs-InP and InGaAsN-GaAs, has been undertaken, for the first time, involving threshold characteristics with pressure. In our theoretical study we investigate the factors that influence the material gain performance, the threshold characteristics and the pressure dependence of each of the laser systems. We find that AlGaInAs and InGaAsN active layer materials have substantially better material gain performance than the commonly used InGaAsP at room temperature. Both radiative and non-radiative current contributions for laser systems are compared using basic equations, which makes our analysis particularly attractive owing to its simplicity and ability to predict the main effects involved. We have found that the estimated variation of phonon-assisted Auger rates with pressure in the N-based system has a slower decrease than that of the other two laser systems. The threshold carrier density n_(th) in the N-based system increases with pressure whereas it decreases in Al- and P-based laser systems. This opposite variation changes the overall behaviour of the threshold current in these three competing laser systems. Our theoretical calculations indicate a significant increase of the radiative to non-radiative recombination current in the N-based laser system. This result highlights the intrinsic superiority of the N-based laser system.