Formation and Nature of InGaN Quantum Dots in GaN Nanowires

Abstract

InGaN/GaN disk-in-nanowire heterostructures on silicon substrates have emerged as important gain media for the realization of visible light sources. The nature of quantum confinement in the disks is largely unknown. From the unique nature of the measured temperature dependence of the radiative lifetime and direct transmission electron microscopy, it is evident that such self-organized islands (disks) behave as quantum dots. This is confirmed by the observation of single photon emission from a single disk-in-nanowire and the presence of a sharp minimum in the line width enhancement factor of edge emitting lasers having the InGaN disks as the gain media.

High-resolution nonlinear optical spectroscopy of InGaN quantum dots in GaN nanowires

“…Details of the growth procedure can be found in Refs. [22][23][24]. The sample emission wavelength is λ ∼ 620 nm.…”

“…The independence of the PL emission energy on excitation intensity and the width of the resonances suggest that the peaks belong to emission from DINW excitons in individual quantum DINWs or small groups of DINWs [2,24]. The exciton emission energy in individual DINWs is determined by the InGaN disk thickness, diameter and indium concentration [29][30][31], which are known to vary across the sample surface [29].…”

III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

“…33 The increase of s r with temperature, seen in Fig. 2(d), is a trend characteristic of quantum dots 29,32,34 and is not observed for bulk semiconductors, quantum wells, or quantum wires. In these materials, s r generally remains unchanged with temperature.…”

Colloidal III–V Nitride Quantum Dots

“…Unlike the synthesis methods of GaN and InN, the way to prepare InGaN quantum dots are mainly top-down approach, such as plasma-assisted molecular beam epitaxy (PA-MBE) [30], metal-organic vapour phase epitaxy (MOVPE) [31], and metal-organic chemical vapour deposition (MOCVD) [32].…”