Effects of ex situ annealing on quaternary alloy (InAlGaAs) capped InAs/GaAs quantum dot heterostructures on optimization of optoelectronic and structural properties with variation in growth rate, barrier thickness, and seed quantum dot monolayer coverage

Abstract

Self-assembled InAs/GaAs multilayer quantum dots (MQDs) have been widely investigated for their potential application in optoelectronic applications such as lasers and photovoltaic devices. This study focuses on analyzing the use of annealing to manipulate the optoelectronic and physical properties of 10-layer InAs/GaAs MQDs. MQD growth rate and parameters such as the capping layer thickness of the InAlGaAs and GaAs capping combination and monolayer coverage of the seed quantum dot (QD) layer were varied. Increase in the number of QD families for one 700°C annealed sample (A2) showed the effects of growth rate and post-growth annealing. Other two samples (B2 and B3) showed the importance of thick combination capping of InAlGaAs and GaAs in an InAs/GaAs MQD system. Samples B2 and B3 revealed an optimized set of characteristics suitable for thermal stability, as the samples were stable even at 750°C annealing, making them suitable for application in communication lasers.