Herein, integrating GaN quantum dots (QDs) within a resonant cavity is focused on. Utilizing metal-organic vapor phase epitaxy, controlled growth of GaN QDs on AlN is achieved. A deep-UV distributed Bragg reflector (DBR) with high reflectivity in the 250-300 nm range, using AlN and Al0.7Ga0.3N layers to maximize refractive index contrast, is developed. A 50-period DBR achieves 98% reflectivity at a wavelength of 272 nm. Scanning transmission electron microscopy and electron energy loss spectroscopy analyses reveal a trisection of DBR periods, attributed to a Ga composition pulling effect during growth. The real structure's reflectivity is simulated and matched well with measured data, though actual reflectivity is lower than the ideal. Cathodoluminescence studies at T = 17 K show emission peaks from both the DBR and the GaN QDs. Further, single-photon emission is demonstrated with a g(2)(t = 0) value of 0.41 at 272.7 nm, confirming the potential for deep-UV single-photon sources. Additionally, the creation of a planar resonant cavity with enhanced emission intensity and vertical nanopillar structures with an aspect ratio of 11 and a diameter of 400 nm confirm the successful integration of GaN QDs in advanced UV photonic structures.

We discuss state of the art microLED performance for AR and direct view display applications, including a detailed comparison of both InGaN and AlInGaP material systems at various sizes from <2micron to >10micron pixels. In particular, we detail our most recent results on efficiency, gamut coverage, and reliability. We also quantify how sidewall passivation can lead to high IQE for 2 micron scale devices. Further we describe early results for a polychromatic LED demonstration that represents a possible breakthrough display technology.

We present state of the art for microLED materials, devices, and reliability. We show performance efficiencies as a function of current density and device size for InGaN Red, Green, and Blue and AlInGaP Red materials and breakdown EQE into constituent IQE and extraction efficiency. We also present reliability results for these structures across all materials systems. We then review several concurrently developed technologies that serve to maximize microLED performance in application use.

Single-photon emitters with high degrees of purity are required for photonic-based quantum technologies. InGaN/GaN quantum dots are promising candidates for the development of single-photon emitters but have typically exhibited emission with insufficient purity. Here, pulsed single-photon emission with high purity is measured from an InGaN quantum dot. A raw g(2)(0) value of 0.043 ± 0.009 with no corrections whatsoever is achieved under quasi-resonant pulsed excitation. Such a low value is, in principle, sufficient for use in quantum key distribution systems.

We present the design, fabrication, and detailed characterization of a photonic bullseye structure to enhance the single-photon extraction efficiency from self-assembled GaN/AlN quantum dots (QDs) emitting in the UV. Through measurements of single-photon emission under saturated pulsed excitation at 80 MHz, we are able to evaluate photon extraction rates of up to similar to 4.36 MHz into the first element of our NA = 0.4 objective lens. Such a rate clearly exceeds the theoretical maximum for an as-grown GaN/AlN QD, and far exceeds the literature values for GaN QDs measured under similar conditions. Our work shows the strong potential for improvement of III-nitride QD-based quantum emitters toward the development of quantum technologies.

Solid-state devices capable of emitting single photons on demand are poised to allow the development of several photonic quantum technologies. Although high-performance devices have been reported in laboratory settings, the vast majority of experimental demonstrations performed to date have required the assistance of cryogenic cooling. In this perspective article we discuss the general progress and future challenges for the development of single photon emitters capable of operation at higher temperatures: negating the need for costly and cumbersome cryogenic cooling systems and their related vacuum requirements.

We report the discovery and characterization of single-photon-emitting carrier localization centers that are spontaneously formed along misfit dislocations in AlGaN. The emitters exhibit extremely narrow linewidths, which are in some cases narrower than our resolution limit of 35 µeV. Spectral analysis reveals a record-low inhomogeneous broadening (smaller than 20 µeV), which can be characterized as almost spectral-diffusion free. Such narrow linewidths allow for an unprecedented discussion of the homogeneous linewidths of quantum emitters in the III-nitrides and, in the current case, provide a lower bound on the pure-dephasing time T2 of ∼200 ps. These experimental results will pave the way to further improve the performance of III-nitride low-dimensional nanostructure-based quantum emitters.

Semiconductor quantum dots (QDs) of various material systems are being heavily researched for the development of solid state single photon emitters, which are required for optical quantum computing and related technologies such as quantum key distribution and quantum metrology. In this review article, we give a broad spectrum overview of the QD-based single photon emitters developed to date, from the telecommunication bands in the IR to the deep UV.

We present a detailed analysis of the second-order correlation behavior of photons emitted from an InGaN QD in a photonic horn structure in order to discuss the excitation, emission, and environmental dynamics that impact the emission. We report the observation of a clear saturation in the antibunching decay rate as the excitation power is increased. We describe the saturation with a simple model describing a saturating excitation path, possibly via inefficient carrier relaxation into the QD emitting state.

We identify and characterize a novel type of quantum emitter formed from InGaN monolayer islands grown using molecular beam epitaxy and further isolated via the fabrication of an array of nanopillar structures. Detailed optical analysis of the characteristic emission spectrum from the monolayer islands is performed, and the main transmission is shown to act as a bright, stable, and fast single-photon emitter with a wavelength of ~400 nm.

We report the realization of single photon emission from an InGaN quantum dot in a GaN inverted truncated-pyramid structure: a single photon horn. The structural parameters of the quantum dots, especially the quantum confinement in the (0001) direction, are well controlled by optimizing the planar single InGaN quantum well to be of ∼2 monolayers. Based on conventional nanoimprint pillars combining with a simple regrowth process, the single photon horn structure is realized with an efficient photon emission of 8 × 105 photons/s while still maintaining a g(2)(0) < 0.5 even at an extremely low excitation power of 35 nW (4.5 W cm−2).

III-nitride quantum dots are proving to be promising for application to single photon emitting devices. Research around the globe is revealing several interesting properties of these emitters, including a wide range of emission wavelengths, high temperature operation, and deterministic polarization of the emitted photons. Here a review is given on the single photon emission properties of such III-nitride quantum dots.

We demonstrate high-purity single-photon emission from a high-quality and further confined InGaN (indium gallium nitride) quantum disc in a GaN (gallium nitride) nanowire fabricated by an unconventional and versatile reverse-reaction fabrication method. This further confined structure exhibits single-photon emission with a g (2) (0) value of 0.11 at 8 K with a sub-nanosecond radiative lifetime. The formation of the further confined structure using this versatile reverse-reaction fabrication approach overcomes many limitations in conventional self-assembled III-nitride nanowires and, thus, exhibits a strong potential application as a high-purity single-photon source.

We report the observation and characterization of sharp emission lines from Zn-related emission centers in GaN. Initial studies on the emission lines show that they appear only at low temperatures (T < 50 K), are energetically stable, and exhibit linewidths of a few meV. A brief discussion on their possible origins is given.

A detailed temporal analysis of the spectral diffusion phenomenon in single photon emitting InGaN/GaN quantum dots (QDs) is performed via measurements of both time-varying emission spectra and single photon emission intensity autocorrelation times. Excitation dependent phenomena are investigated via the optical excitation of carriers into the GaN barrier material and also directly into InGaN. Excitation into InGaN reveals that the fastest environmental fluctuations occur on timescales as long as a few hundreds of nanoseconds: an order of magnitude longer than previously measured in GaN QDs. Such long time scales may in future allow for the generation of indistinguishable photons in spite of the fact that the experimentally measured linewidths are broad.

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.