Impact of quantum dots on III-nitride lasers: a theoretical calculation of threshold current densities

Abstract

Abstract We present a theoretical study on the gain and threshold current density of III-nitride quantum dot (QD) and quantum well (QW) lasers with a comprehensive theory model. It is found that at transparency condition the injection current density of QD lasers is about 120 times lower than QW lasers in III-nitrides, while in III-arsenide it is about 15 times. It means that using QDs in III-nitride lasers could be 8 times more efficient than in III-arsenide. This significant improvement in III-nitrides is due to their large effective-masses and the large asymmetry of effective-masses between valence bands and conduction bands. Our results reveal the advantages of using QD for low threshold laser applications in III-nitrides.