Abstract
Precisely ordered arrays of InAs quantum dots are formed on a nanoisland-structured GaAs (100) surface using in situ laser interference during self-assembled molecular beam epitaxial growth. Nanoislands induced by single-pulse four-beam laser interference act as preferential nucleation sites for InAs quantum dots and result in site occupation dependent on the size of nanoislands, the InAs coverage, and the laser parameters. By optimizing the growth and interference conditions, regular dense ordering of single dots was obtained for the first time using this in situ noninvasive approach. The photoluminescence spectra of the resulting quantum dot arrays with a period of 300 nm show good optical quality and uniformity. This technique paves the way for the rapid large-scale fabrication of arrays of single dots to enable quantum information technology device platforms.
Highlights
Low-dimensional semiconductor nanostructures such as quantum dots (QDs) and nanowires (NWs) have shown significant potential for applications in optoelectronics and nanoelectronics, e.g., low-threshold lasers, single electron transistors, and quantum memory devices,[1−3] because of the unique nature of their quantized electronic states
As ideal solid-state single photon or entangled photon sources, self-assembled QDs have enabled a wealth of new physics and device applications in the fields of quantum information processing and communication.[4−7] For instance, single QDs coupled to a microcavity mode are able to achieve long-range spin−spin interactions[8] and long spin decoherence times for electrons and holes were reported based on spin-based qubits in III−V semiconductor QDs.[9]
We investigated the growth, structural, and optical properties of InAs QD arrays formed in situ during molecular beam epitaxy (MBE)
Summary
Low-dimensional semiconductor nanostructures such as quantum dots (QDs) and nanowires (NWs) have shown significant potential for applications in optoelectronics and nanoelectronics, e.g., low-threshold lasers, single electron transistors, and quantum memory devices,[1−3] because of the unique nature of their quantized electronic states. The underlying mechanisms behind these observations are somewhat unclear, with Clegg et al.[18] suggesting a surface diffusion process while Zhang et al.[19] attributing their observations to the thermal desorption of indium None of these works shows the presence of an intermediate surface structuring step before the nucleation of the nanowires or QDs. precisely controlled single dot arrays were not achieved and associated optical properties have never been reported. We investigated the growth, structural, and optical properties of InAs QD arrays formed in situ during molecular beam epitaxy (MBE). We applied single-pulse four-beam laser interference during the epitaxial growth step. One monolayer (ML) of InAs was deposited at different growth rates (0.079, 0.04, and 0.026 ML s−1), immediately followed by in situ single-pulse laser interference patterning. After 10 s of growth interruption under As2 flux, the samples were quenched and taken out from the chamber for structural characterization
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