Photon correlation study of background suppressed single InGaN nanocolumns

Abstract

We report on a linearly polarized non-classical light emission from a single InGaN/GaN nanocolumn, which is a site-controlled nanostructure allowing for pixel-like large-scale integration. We have developed a shadow mask technique to reduce background emissions arising from nitride deposits around single nanocolumns and defect states of GaN. The signal to background ratio is improved from to , which allows for detailed polarization-dependent measurement and photon-correlation measurements. Polarization-dependent measurements show that linearly polarized emissions arise from excitonic recombination involving a heavy-hole-like electronic state, corresponding to the bulk exciton of an in-plane polarized A exciton. The second-order coherence function at time zero g (2)(0) is 0.52 at 20 K without background correction. This value is explained in terms of a statistical mixture of a single-photon emission with residual weak background emissions, as well as efficient carrier injection from other localized states.

Emission of Linearly Polarized Single Photons from Quantum Dots Contained in Nonpolar, Semipolar, and Polar Sections of Pencil-Like InGaN/GaN Nanowires

“…These values are all well below the 0.5 two-photon threshold, and thus unambiguously show the quantum nature of the emission from the actual localization centers in all three polarity regions. To check consistency with previous reports on III-nitride emitters, [3][4][5][6][7][8][10][11][12]14,15 the optical polarization from selected nonpolar, semipolar and polar single photon emission centers has also been measured (see figure 6 for representative measurements). The polarization measurements were performed with respect to a randomly chosen fixed axis.…”

“…Indeed single photon emission has already been demonstrated over range of 280 -620 nm using III-nitride quantum dots (QDs) of different material composition. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] In addition, the benefits of high band offsets in III-nitride heterostructures have been exploited for strong exciton confinement, thus allowing single photon operation at room temperature 8,9 and even in hot environments (77 ˚C). 13 In other advances, a certain degree of single photon polarization control has been achieved via manipulation of the emitting QD shape, 6,12 and electrically excited single photon emission has also been reported for both columnar and bulk device morphologies.…”

“…4,8 Many of the recent advances in the field of III-nitride-based single photon sources (SPSs) have been achieved using QDs embedded in nanowire (NW) structures. 4,[8][9][10][11][13][14][15] Owing to their high crystal quality, GaN NWs can be used to host QDs with superior crystal structure. Furthermore, embedding the QDs into site-controlled NWs allows control over their precise locations.…”

“…The key features of III-nitrides which make them a material of choice for classical light emission also qualify them as promising candidates for efficient quantum light emitters that can be operated over a wide spectral range and at high temperatures. Indeed single photon emission has already been demonstrated over range of 280–620 nm using III-nitride quantum dots (QDs) of different material composition. − In addition, the benefits of high band offsets in III-nitride heterostructures have been exploited for strong exciton confinement, thus, allowing single photon operation at room temperature , and even in hot environments (77 °C) . In other advances, a certain degree of single photon polarization control has been achieved via manipulation of the emitting QD shape, , and electrically excited single photon emission has also been reported for both columnar and bulk device morphologies. , …”

Nitride single photon sources

“…Horizontally lying nanowires are the most straightforward solution [52,66,72,116]. The different dimensions between a nanowire's length and width naturally creates a large anisotropy.…”