Improvement of single photon emission from InGaN QDs embedded in porous micropillars

Abstract

In many InGaN/GaN single photon emitting structures, significant contamination of the single photon stream by background emission is observed. Here, utilizing InGaN/GaN quantum dots incorporated in mesoporous distributed Bragg reflectors (DBRs) within micropillars, we demonstrate methods for the reduction of this contamination. Using the resulting devices, autocorrelation measurements were performed using a Hanbury Brown and Twiss set-up, and thus, we report a working quantum dot device in the III-nitride system utilizing mesoporous DBRs. Uncorrected g(2)(0) autocorrelation values are shown to be significantly improved when excited with a laser at longer wavelengths and lower powers. Through this optimization, we report a g(2)(0) value from a blue-emitting InGaN/GaN quantum dot of 0.126 ± 0.003 without any form of background correction.

Single-photon emission from isolated monolayer islands of InGaN

“…For this representative emitter, we obtain P sat = 1.66 ± 0.15 μW and I ∞ = 1.54 ± 0.08 × 10 5 counts/s. This intensity value is comparable to that of other single emitters in QDs or 2D materials 20,23,47,48 . We note that even with our low excitation power of 0.5 μW, as shown in Fig.…”

Spectral diffusion time scales in InGaN/GaN quantum dots

“…Thomas Swan close-coupled showerhead reactor and are situated in an etched micro-pillar structure containing porous DBRs (formed by electrochemical etching) for enhanced emission extraction efficiency. 35,36 Due to the modified droplet epitaxy growth of the QDs, they form as part of a fragmented quantum well. 32,37 Characterization of the QDs is performed optically using microphotoluminescence spectroscopy at a temperature of 7 K in a closed cycle cryostat under continuous wave (CW) laser excitation.…”

Single‐photon emission from a further confined InGaN/GaN quantum disc via reverse‐reaction growth

“…We note that the value of g (2) (0) we present here is comparable with the most pure single-photon emission reported to date from the InGaN/GaN material system of various nanostructure geometries. 21,46 The residual nonzero g (2) (0) value is due to the unfiltered spectral background contamination that enters the HBT setup during the measurement. Analysis of the background level in Figure 3A allows us to estimate a background-corrected g (2) (0) value of approximately 0.05, essentially zero to within the experimental error, 47 indicating that the QD itself is a very pure single-photon emitter (although we note that it is the measured value of 0.11 that truly represents the degree to which the QD/nanowire system is able to provide single photons).…”