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

Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

“…In multilayers of InAs/GaAs QDs, it has been reported that annealing at 700ºC produces a decrease of the size of the QDs likely due to the diffusion of In, increasing the number of nanostructures. For very high annealing temperatures (800ºC), most of the QDs disappear because In atoms diffuse into the wetting layer [14]. Also, studies in InGaAs/GaAs QDs have shown that annealing at 750ºC reduces the strain field in the QDs because of the reduction in their size, probably due to the diffusion of In to the wetting layer [11].In our high-resolution analysis, we have obtained experimental evidence of Sb out-diffusion from the QDs, as shown by the intensity ratio map in Fig.…”

“…Many studies have showed that heating treatments improve the crystal quality of semiconductor heterostructures. For example, in AlGaN thin films [10] and in InAs/GaAs QDs [14], a reduction in the density of threading dislocations after the heating process has been reported.…”

“…Application of a conventional ex-situ technique to this a sample would have a very drastic and damaging effect on the quantum dots which are near the surface of our sample.The effect of these thermal annealing on the structural quality of semiconductor materialsis frequently measured indirectly, through the analysis of the optoelectronic properties of the material [11][12][13]. Some works have been published where the effect of the application of a thermal treatment tosemiconductor materials is analyzed by direct measurements in order to study the structural quality of the sample, for example, byconventionaltransmission electron microscopy [10,14]. These analyses provide information on the nanometer scale.…”

“…These analyses provide information on the nanometer scale. For example, the application of a thermal annealing in InAs/GaAs QDshas shown to reduce the density of threading dislocations and to have some effect on the size ofthe nanostructures [14].However, only the analyses at atomic column resolution can provide a complete picture of the effect of a thermal annealing in order to obtain a better understanding of this thermal treatment. In this work, we analyze by aberration corrected HAADF-STEM and EELS the effect of an in-situ thermal annealing on the structural quality ofheterostructures of GaSb/GaAs QDs.…”

Electronic and optical properties of InGaAs/GaAs quantum dots with tunable aspect-ratio

“…[1][2][3][4] The InGaAs/GaAs QDs have shown their unique quantum properties in applications of infrared photodetectors, solar cell, and single-photon emitter. [5][6][7][8][9] InGaAs QDs are usually fabricated by the Stranski-Krastanov (SK) epitaxial growth.…”