Single Photon Emission from Site-Controlled InAs Quantum Dots Grown on GaAs(001) Patterned Substrates

Abstract

We present a fabrication method to produce site-controlled and regularly spaced InAs/GaAs quantum dots for applications in quantum optical information devices. The high selectivity of our epitaxial regrowth procedure can be used to allocate the quantum dots only in positions predefined by ex-situ local oxidation atomic force nanolithography. The quantum dots obtained following this fabrication process present a high optical quality which we have evaluated by microphotoluminescence and photon correlation experiments.

Exciton and multiexciton optical properties of single InAs/GaAs site-controlled quantum dots

“…[13][14][15][16] A few years ago, it was demonstrated that InAs QDs grown on GaAs(001) substrates patterned by means of lithography techniques behave as single photon emitters. 17 Since that moment, a great effort has been devoted to optimize the optical properties of site-controlled QDs (SCQDs). 18 Nowadays, the wafer can be patterned by different techniques such as e-beam, focused ion beam, or atomic force microscopy (AFM), among other lithography methods.…”

“…This process efficiently removes the patterned oxide motifs, leading to the formation of nanoholes at the predefined positions while providing a clean surface for the growth of nanostructures with good optical properties. 17 Prior to InAs deposition, a 15 nm thick GaAs buffer layer is grown at low temperature (T S ¼ 490 C) in order to preserve the pattern motifs. On top of the GaAs buffer layer, 1.5 monolayers (ML) of InAs are deposited at a growth rate of 0.01ML/s at T S ¼ 490 C. This InAs coverage is below the critical thickness for QD formation as observed by 2D-3D RHEED transition on non-patterned substrates (1.7 ML) under these growth conditions, but it is enough for obtaining nucleation of InAs inside the nanoholes to fabricate InAs SCQD.…”

“…The InAs are distributed forming shallow nanostructures about 7 nm height and 90 nm width, as concluded from AFM characterization. 17 This reduced aspect ratio (height to width) suggests disk-or lens-like nanostructures. After 2 min of growth interruption under As 4 flux, samples are capped with 20 nm thick GaAs layer for optical characterization.…”

The Role of Groove Periodicity in the Formation of Site-Controlled Quantum Dot Chains

“…In molecular beam epitaxy (MBE) processes, this can be achieved by defining the nucleation sites for impinging atoms using patterning the surface. Patterning is usually accomplished by lithographic techniques, such e-beam lithography [7][8][9][10][11], nanoimprint lithography [12], interference lithography, photolithography [13], or atomic force microscopy (AFM) lithography [14].…”

High quality factor GaAs-based photonic crystal microcavities by epitaxial re-growth

“…Among them, local oxidation lithography by atomic force microscopy (LOL-AFM) is a powerful technique for the patterning of GaAs substrates which is compatible with the epitaxial growth of site-controlled InAs QDs. LOL-AFM allows the positioning of high quality QDs in any place of a wafer in a deterministic way [17], and therefore is very promising for quantum photonic applications [15,16]. However, since the QD has to be embedded in the PCM slab underneath the surface, the development of a special re-growth procedure is needed to complete the photonic structure after the LOL-AFM step.…”