Current injection lasing operation of self-formed GaP/InP superlattice quantum dot laser diodes

摘要

Self-formed quantum dot (QD) structures are gathering great interest for novel device applications and physical studies. Recently, we found that high lateral density ( approx 10~(11) cm~(-2)), well-aigned QDs are self-formed by growing (GaP)n(InP)m short period superlattice (n, m approx 1-2) on GaAs (N11)A substrate by gas ource molecular beam epitaxy MBE). We have already reported the transmission electron microscopy (TEM) and scanning tunneling microscopy (STM) observations of these QDs and their optical properties [1, 2]. Light emitting diodes (LEDs) were also fabricated using multilayer QDs (MQDs) sandwiched with In_(0.49)Ga_(0.51)P barrier layers as an active layer and In_(0.49)Ga_(0.51)P as cladding layers [1]. Although their optical properties were improved with decreasing superlattice cycles, their energy level became close to that of barrier layers indicating insufficient carrier confinement along verticall directions [1]. In this paper, we will study the effect of the InGaP/InAlP superlattice (SL) barrier and cladding layers instead of InGaP layers on the optical properties of modified MQD structures. Photoluminescence (PL) as well as electroluminescence (EL) properties are discussed. In addition, we report the first current injection lasing operation of this modified MQD laser diodes.