The impact of monolayer coverage, barrier thickness and growth rate on the thermal stability of photoluminescence of coupled InAs/GaAs quantum dot hetero-structure with quaternary capping of InAlGaAs

Fabrication of InxGa1−xN/GaN QDs with InAlGaN capping layer by coaxial growth on non-(semi-) polar n-GaN NWs using metal organic chemical vapor deposition for blue emission

“…5b). We suspect, this In-Ga interdiffusion did not provide a smooth growth front for growing the successive QD layers 32,44 and as a result, most of the surface QDs were merged or decomposed (Fig. 5b-2) during deposition.…”

“…7c) over In x Ga 1Àx N QDs was not enough to compensate for the strain propagating from the seed layer of dots. 32 Thus, the propagated strain from the seed layer of QDs played an important role during the formation of the second layer of dots, making them vertically coupled and larger in size. 37,43 Both inhomogeneous and homogeneous strain in the system 37 were not enough to produce threading dislocations and defects through the GaN barrier layer, 32 as clearly shown in Fig.…”

“…31 As a result of variation in the inhomogeneous surface strain over a QD layer, the indium atoms from the quaternary InAlGaAs alloy diffuse into the vicinity of dots near the elastically relaxed regions, thereby forming an indium concentration gradient along the periphery of the QD islands. 32 This concentration gradient helps in preventing the outdiffusion of indium atoms from the dots during the growth of the capping layer. 31 Both Chakrabarti et al 33 and Mandal et al 34 established the fact that InAlGaAs capping helped in improving the device performance of InGaAs/GaAs QD based infrared photodetectors.…”

Effect of high energy proton implantation on the device characteristics of InAlGaAs-capped InGaAs/GaAs quantum dot based infrared photodetectors

“…suggested that the implantation with hydrogen ions increases the dots size [11][12][13] . Energy imparted by high energy hydrogen ions increases the mobility of the Al atoms in the quaternary alloy, resulting in greater replacement of In atoms at the wetting layer.…”

In-Situ Tailoring of Vertically Coupled InAs p-i-p Quantum-Dot Infrared Photodetectors: Toward Homogeneous Dot Size Distribution and Minimization of In–Ga Intermixing

“…This not only leads to the aforementioned shortcomings but also delimits the number of repetitions of QD layers possible in the active region. Previously, researchers have tried to address this issue by several modifications in growth techniques such as (i) optimizing the GaAs spacer layer between the dots, 21 (ii) varying the monolayer coverage, 22 (iii) introducing a strain reducing layer, 23 etc. In this study, we attempt to circumvent these problems by proposing an in situ growth strategy for the formation of highly homogeneous, strain-coupled, defect-less dot layers, which turns out to be a coalescence of some of the strategies enlisted earlier.…”