Quantum Optoelectronics

Abstract:

We have investigated, using micro-photoluminescence, the quantum confined Stark effect in an InxGa1 - xN/GaN multi-quantum disk structure at the tip of a single GaN nanorod. A strong and sharp emission line from the InxGa1 - xN/GaN quantum disks near 3.26eV was observed. The peak energy of the emission line was observed to blue-shift with increasing excitation power, indicating a quantum confined Stark effect. Furthermore, both the blue-shift and the intensity of the emission saturate with increasing excitation power. The temperature-dependence of the 3.26eV emission line has also been investigated. © 2010 IOP Publishing Ltd.

Abstract:

Cavity-enhanced single-photon emission in the blue spectral region was measured from single InGaN/GaN quantum dots. The low-Q microcavities used were characterized using micro-reflectance spectroscopy where the source was the enhanced blue output from a photonic crystal fibre. Micro-photoluminescence was observed from several cavities and found to be ~10 times stronger than typical InGaN quantum dot emission without a cavity. The measurements were performed using non-linear excitation spectroscopy in order to suppress the background emission from the underlying wetting layer. © The Author(s) 2009.

Abstract:

We have investigated the optical properties of bulk-like GaN nanorods by cathodoluminescence measurements at room temperature. The bulk-like nanorods were grown on a Si (111) substrate by rf-plasma assisted molecular beam epitaxy and are characterized be being surrounded by a compact region. A weak and broad emission line near 3.36 eV was observed at an accelerating voltage of 5 kV. This emission occurs at a lower energy than the emission from unstrained GaN nanorods that protrude from the compact region. Upon increasing the electron beam energy, and hence investigating regions deeper in the sample, the peak emission energy redshifts due to the strain at the substrate interface. The behaviour of the emission line is further investigated with cathodoluminescence measurement on single nanorod's. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Abstract:

The fabrication of nano-rods containing InGaN/GaN quantum wells with diameter and the evolution of their optical properties are reported. A prototype nano-rod array LED device with strong photonic crystal effects in its electroluminescence is demonstrated. © OSA / ANIC/SOLED 2010.