Local droplet etching on InAlAs/InP surfaces with InAl droplets

Abstract

GaAs quantum dots (QDs) grown by local droplet etching (LDE) have been studied extensively in recent years. The LDE method allows for high crystallinity, as well as precise control of the density, morphology, and size of QDs. These properties make GaAs QDs an ideal candidate as single photon and entangled photon sources at short wavelengths (<800 nm). For technologically important telecom wavelengths, however, it is still unclear whether LDE grown QDs can be realized. Controlling the growth conditions does not enable shifting the wavelength of GaAs QDs to the telecom region. New recipes will have to be established. In this work, we study Indium–Aluminum (InAl) droplet etching on ultra-smooth In0.55Al0.45As surfaces on InP substrates, with a goal to lay the foundation for growing symmetrical and strain-free telecom QDs using the LDE method. We report that both droplets start to etch nanoholes at a substrate temperature above 415 °C, showing varying nanohole morphology and rapidly changing density (by more than one order of magnitude) at different temperatures. Al and In droplets are found to not intermix during etching, and instead etch nanoholes individually. The obtained nanoholes show a symmetric profile and very low densities, enabling infilling of lattice-matched InGaAs QDs on InxAl1−xAs/InP surfaces in further works.

Surface Modification of Gallium Arsenide by Electrochemical Methods in Different Electrolyte Compositions

“…Among all semiconductors, the largest variety of surface modification by the electrochemical methods was achieved for the crystals of type А 3 В 5 , including InP, GaAs, GaP. 26,27 Thus, the possibility for synthesizing the nanoneedles, nanowires, textured and porous surfaces, was repeatedly shown. 28,29 The heterostructures consisting of the layers of the semiconductor's own oxide can be also formed on the semiconductor surface by the electrochemical treatment methods.…”