Low-Density Quantum Dot Molecules by Selective Etching Using in Droplet as a Mask

Abstract

We demonstrate low-density quantum dot molecules (QDMs) by selective etching using In droplets as a mask. Selective etching is performed with InGaAs QDMs buried underneath GaAs capping layer, on which In droplets are formed by droplet epitaxy using molecular beam epitaxy. During the chemical etching, the droplets act as a mask and QDMs underneath the droplets that only survive. Photoluminescence measurement from the selectively etched QDMs in mesa structures shows a much reduced intensity, which indicates low-density QDMs. This technique provides a simple and flexible method to attain low-density QDMs. The density can be easily modified by the control of the size and density of In droplets, which is suitable for single QDM spectroscopy and for their device applications.Index Terms-Atomic force microscopy (AFM), droplets, low density, molecular beam epitaxy (MBE), photoluminescence (PL), quantum dot molecules (QDMs), selective etching.

Fabrication of low-density GaN/AlN quantum dots via GaN thermal decomposition in MOCVD

“…However, challenges remains in fabrication of low-density GaN quantum dots (QDs) with high quality. On the one hand, the most frequently used fabrication approach is self-assembly process via Stranski-Krastanov (SK) growth mode which requires sufficient lattice mismatch, but it is harder to acquire low-density GaN QDs and usually results in randomly distributed QDs with different sizes [10,11]. On the other hand, although some low-density GaN nanodots can be obtained by the droplet epitaxy technique based on a vapor-liquid-solid process which offers distinct advantages in size and density manipulation of QDs, the droplet epitaxy technique usually results in QDs with the incomplete transition from Ga droplet to crystal GaN.…”

Formation of Ga droplets on patterned GaAs (100) by molecular beam epitaxy

“…QD molecules [15-19], low-density QDs [20], ensembles of quantum ring geometry and droplet [21], and various nanostructure complexes [22,23] have been demonstrated by the D-E approach. In addition, nanohole drilling and local etching effect [24-26], selective etching using droplet as a mask [27,28], various configurations of In nanocrystals [29,30], running droplets [31-33], and Ga-triggered oxide desorption [34,35] are only a few examples of D-E applications.…”