Single InGaN nanocolumn spectroscopy

Abstract

We report on spectroscopy of single InGaN/GaN nanocolumns, which are site-controlled nanostructures allowing for pixel-like large-scale integration. A single nanocolumn shows a narrow photoluminescence around 600 nm at 20K, the linewidth of which ranges between 0.1 and 10 meV. Single nanocolumns show distinct photoluminescence even at 90K. We also observe an interesting temperature dependence of the integrated intensity having its maximum at 70 K, which suggests efficient carrier injection into the localized states. The results suggest that the nanocolumns provide a promising platform for large-scale integration of single photon emitters and future integration of qubits.

Selective Area Sublimation: A Simple Top-down Route for GaN-Based Nanowire Fabrication

“…Note that similar line widths were reported for single GaN quantum dot in nanowires . These sharp lines can be observed up to a temperature of 20 K, which is significantly lower than previous works regarding isolated nanopyramid (70 K), quantum dots resulting from Stranski–Krastanov growth mode (150 K), or single disk in nanowire (90 K) . We have to point out that the density of In x Ga 1– x N QDisks is still too large to isolate a single QDisk.…”

“…47 These sharp lines can be observed up to a temperature of 20 K, which is significantly lower than previous works regarding isolated nanopyramid (70 K), 48 quantum dots resulting from Stranski−Krastanov growth mode (150 K), 49 or single disk in nanowire (90 K). 50 We have to point out that the density of In x Ga 1−x N QDisks is still too large to isolate a single QDisk. This goal can however be achieved by decreasing further the nanowire density by reducing the SiN x surface coverage and by growing a single In x Ga 1−x N QW instead of a MQW.…”

Photon correlation study of background suppressed single InGaN nanocolumns

“…Nanocolumns are selectively formed one-dimensional columnar nitride nanocrystals, and have been intensively studied for light-emitting diode (LED) applications because of their highly tunable emission energy in the range of 400-1800 nm [1][2][3][4][5][6][7][8] and their high-density large-scale integration capability. Regularly arranged nanocolumns in a triangular lattice with a 300 nm lattice constant were reported in 2014, 7) and a monolithic integration of LEDs with an area of 150 × 150 µm 2 was realized.…”

“…Each of the densely integrated nanocolumns shows intense and narrow quantum dot (QD)-like photoluminescence (PL) lines up to 90 K, suggesting deep confinement potentials suitable for quantum information devices. 8) High-temperature operation of single-photon emitters, based on deep confinement potentials, has been reported in various III-nitride systems. A triggered single-photon emission at room temperature was demonstrated in sitecontrolled GaN=AlGaN nanowire QDs.…”

“…20,21) Single nanocolumns provide sharp emission lines arising from the excitons confined in InGaN potential minima. Some of the emission lines at 90 K are still higher than that at 20 K. 8) The major obstacle to applying the nanocolumn system in single-photon emitters has been the existence of background emissions from the surroundings of the nanocolumns. We show that the background emissions are highly suppressed by a shadow mask technique in combination with a crystal lift-off process.…”