Improvement of InAs quantum-dot optical properties by strain compensation with GaNAs capping layers

Abstract

Two kinds of self-assembled InAs quantum dots ͑QDs͒ grown on GaAs ͑001͒ substrates were studied. One is capped with GaAs layers and the other with GaNAs strain-compensating layers. Photoluminescence ͑PL͒ measurements on the two kinds of InAs QDs showed distinct dependence on the selection of the capping layers. The homogeneity and luminescence efficiency of the InAs QDs were much improved when the net strain was reduced with GaNAs layers. These results demonstrate the importance of net strain compensation for the improved optical quality of InAs QDs.

The role of high growth temperature GaAs spacer layers in 1.3-/spl mu/m In(Ga)As quantum-dot lasers

“…However, stacking multiple QD layers modifies the growth of subsequent layers, which in the extreme results in defect formation as a consequence of the increasing amount of strained material deposited. Solutions include strain compensation [3], [4], removal of the largest dots by selective evaporation [5], and the use of high growth temperature spacer layers (HGTSLs) between QD sheets, which have recently been demonstrated to greatly enhance device characteristics in multilayer 1.3-m In(Ga)As QD lasers [6], [7]. This letter describes the measurement of gain and loss of five-layer QD laser material with and without HGTSLs to reveal the mechanisms responsible for this improvement.…”

The application of an InGaAs∕GaAsN strain-compensated superlattice to InAs quantum dots

“…͑Color online͒ Low temperature ͑20 K͒ and room temperature ͑300 K͒ PL spectra of the samples capped with one, two, and three pairs of InGaAs͑1.1 nm͒ / GaAsN͑1.1 nm͒ SCSLs. effect 1,7 of the In 0.375 Ga 0.625 As layer and the strain compensating effect 4,10 of the GaAs 0.978 N 0.022 layer, which made the redshift approaching the In 0.375 Ga 0.625 As capping layer possible in spite of the weak average strain of 0.65%.…”

“…4,5 Meanwhile, superlattice ͑SL͒ structures are frequently used as buffer layers in optoelectronic devices to improve the crystalline quality by capturing defects at heterointerfaces. 6 Based on the above considerations, we proposed an application of InGaAs/ GaAsN strain-compensated superlattice ͑SCSL͒ as a barrier layer of InAs QDs.…”

Changes in Optical Properties of GaAsN During Annealing

“…The predicted reduction of band gap in GaAsN alloys due to the band gap bowing has been clearly demonstrated, which is dependent on the N composition [2][3][4][5]. Surprisingly, the majority of the quantum dot (QD) studies involving GaAsN have involved InAs QDs with a GaAsN overlay to reduce strain [6,7]. In this work we report on our studies of annealing GaAsN thin layers and QD-like structures.…”