Temperature Dependence of the Emission Spectrum of GaN Defect Single-Photon Emitters

Kavli Affiliate: Farhan Rana

| First 5 Authors: Yifei Geng, Jialun Luo, Len van Deurzen, Huili, Xing

| Summary:

Single-photon emitters (SPEs) in technologically mature wide bandgap
semiconductors are attractive for realizing integrated platforms for quantum
applications. We investigate single-photon emitters in GaN. GaN hosts bright
and stable single-photon emitters in the 600 nm to 700 nm wavelength range with
strong zero phonon lines (ZPL) even at room temperature. We study the
temperature dependence of the ZPL spectra of SPEs integrated with solid
immersion lenses. At temperatures below ~50 K, the ZPL lineshape is found to be
Gaussian and the ZPL linewidth is temperature independent and dominated by
spectral diffusion. The linewidth increases monotonically with the temperature.
At temperatures above ~125 K, the lineshape becomes Lorentzian and the
temperature dependence of the linewidth does not follow a power law in contrast
to defect emitters in SiC and diamond. We propose a model in which decoherence
caused by absorption/emission of optical phonons in an elastic Raman process
determines the lineshape and the linewidth at high temperatures. With spectral
diffusion included, our complete model explains the temperature dependence of
the ZPL linewidth in the entire 10 K to 270 K temperature range explored in
this work. The ~19 meV optical phonon energy extracted by fitting the model to
the data matches remarkably well the ~18 meV zone center energy of the lowest
optical phonon band E2(low) in GaN. Our work sheds light on the mechanisms
responsible for linewidth broadening in GaN SPEs.

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