Formation of self-assembled InAs quantum dots on InAl(Ga)As/InP and effects of a thin GaAs layer

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

“…In order to improve the inhomogeneous broadening of Qdash multi-stack structure, the concept of growing ultrathin (~2 ML) GaAs layer on InGaAlAs barrier layer before InAs deposition for the Qdash formation was reported by Mi et al [186] who demonstrated an improvement in the optical quality (> 3 times increase in the PL intensity) as illustrated in Fig. 27(a) and is coherent with other reports [36]. A dramatic enhancement (> 10 times) in PL intensity with reduced PL linewidth of ~50 meV at room temperature was observed if additional GaAs layers were deposited after the growth of 5 nm InGaAlAs capping layer.…”

“…For instance, the role of buffer layer surface morphology and alloy contents was examined in Ref. [22] as they affect the formation of the nanostructures; growth of high density InAs nanostructures resembling like elongated Qdots [36]; sparsely populated InAs nano-islands [37] on InGaAs, InAlAs, and InP buffer layers on (100) InP [23]. In this respect, Stinz et al [38] suggested the utilization of vicinal (100) InP substrates for the growth of InAs Qdots.…”

“…For InAs deposited directly on InAlAs buffer layer, Qdashes elongated along [-110] are formed with an average ~25 nm width and 3.5×10 in density were observed. In another study, Kim et al utilized thin underlying GaAs [36] and InGaAs [41] layer as a means to control the optical and structural properties of InAs Qdots grown on latticed matched InGaAlAs matrix on (100) InP substrate. Increasing the GaAs layer thickness from 0.8 nm to 1.6 nm blue shifted the PL emission wavelength and resulted in reduced PL intensity.…”

A novel approach to increase emission wavelength of InAs/GaAs quantum dots by using a quaternary capping layer

“…Maximov et al [11] showed that when InAs QDs are capped by an InAlGaAs alloy layer, ac− tivated alloy phase separation (AAPS) leads to strain driven migration of indium atoms from the capping layer to the dots which causes an increase in width and height of the InAs QDs. Indium concentration in the QDs increases caus− ing a local compositional deviation of group III atoms in the phase separated InAlGaAs alloy [12,13]. This causes the growth front for subsequent QD layers to become uneven.…”

Atomic Force Microscopy Characterization of Carbon Nanotubes

“…Another important reason for using this characterization is that there is almost no restriction on the sample to be analysed. Many researchers use the AFM in different areas [15][16][17][18]. Semiconductors, biotechnology, life sciences, materials, and surface characterizations are typical applications.…”