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Single photons from a hexagonal micro-pyramid

 

In short: Single photon sources are both of fundamental interest and a common condition for quantum information applications. In this paper we report on single photon emission from an InGaN quantum dot formed on the apex of a site-controlled hexagonal GaN micropyramid. An approach to efficiently suppress uncorrelated emission from the pyramid base with a processed metal film is demonstrated to significantly enhance the signal-to-background ratio of the emission.

The generation of non-classical light is both of fundamental interest and a common condition for quantum information applications. Semiconductor quantum dots are feasible single photon emitters for such applications due to their atomic-like energy structure and their possibility to be integrated with other semiconductor devices on the same chip. Site-controlled quantum dot operating close to room temperature are needed for widespread applications, and linearly polarized emitters are a prerequisite for certain quantum information applications. III-nitride quantum dots have attractive properties such as deep confinement potentials - needed for high temperature operation - and a high degree of linear polarization of the emitted photons already for weakly asymmetric quantum dots.

In this paper we report on single photon emission from an InGaN quantum dot formed on the apex of a hexagonal GaN micropyramid. An approach to efficiently suppress uncorrelated emission from the pyramid base with a processed metal film is demonstrated to significantly enhance the signal-to-background ratio of the emission. As a result, the single photon emission properties at low temperatures of -260 C are significantly improved.  Moreover, it is demonstrated that dominating single photon emission to survive up to -220 C. The deterioration of the single photon statistics at elevated temperatures is well understood with a model proposed in our earlier work. By the means of single photon correlation measurements, we have also - for the first time in this pyramidal quantum dot system - identified temporally bunched photons of different energies.

These results underline the great potential of InGaN quantum dots on site-controlled micropyramids as sources of fast polarized single photons suitable as light sources for secure communication and other quantum information applications.

Details of the research are described in Nanotechnology 26, 065702 (2015)
doi:10.1088/0957-4484/26/6/065702

Contact

Fredrik Karlsson, assoc. professor
Phone: +46 (0)13 28 25 33
E-mail: freka@ifm.liu.se

Funding

  • Carl Trygger Foundation for Scientific Research
  • Swedish Research Council (VR).
  • Nano-N consortium funded by the Swedish Foundation for Strategic Research (SSF).
  • Knut and Alice Wallenberg Foundation (KAW).
  • Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University.
  • Font-D at Linköping University

 


Responsible for this page: Fredrik Karlsson
Last updated: 04/01/15