Electrically-driven silicon single-photon source

Brown University, Providence RI

Investigators

Abstract

Quantum light sources are enablers of quantum information processing, communications, sensing and imaging. Further progress demands single-photon sources that are electrically-driven (i.e. electrically triggered), emit at a low-loss telecom wavelength, and can be miniaturized and integrated with silicon electronic circuits. This project aims to pilot the development of such single-photon sources that are not yet available. Success in this endeavor would represent an unprecedented advance in the field and would help push the boundaries of quantum information technology, which in turn could lead to expansion of our capabilities in advancing optical and materials sciences in the quantum domain. In so doing, the proposed effort will also catalyze transformative advances of our engineering education and training programs towards quantum technologies, thereby not only impacting the training of postdocs, graduates, and undergraduates. The proposed effort leverages a prior limit-breaking effort in generating bright stimulated emission in the telecom O-band (~1.3 μm) from a crystalline silicon patterned with periodically distributed G-centers – also known as the carbon-silicon ‘color-center’. This project too will push the boundary, but to the opposite limit – i.e. to electrically-pumped single-photon emission, which is unprecedented in silicon and monochromatic (zero-phonon). Enabled by the innovative nanopatterning of a Si crystal with a 2D periodic array of nanoscale holes, it would create a periodic distribution of G-centers embedded in the sidewall of the nanohole which is also mechanically strained and bandgap lowered. As demonstrated in our earlier reports, this would allow one to create the emissive G-centers with little increase in the overall optical loss while simultaneously channeling the injected charge carriers to the G-centers for recombination and emission. Furthermore, the periodic patterning will be designed in such a way that the spontaneous emission rate can be enhanced via the Purcell effect. This will be achieved by engineering the structure and periodicity of the nano-hole array to create a photonic crystal with a small mode volume and a high density of photon states to peak at/near the frequency of the G-center emission. An extra enhancement can be achieved by blocking the leakage hole current with a thin barrier layer while still allowing electrons to tunnel through. The photon collection efficiency will be maximized with both the holey low-index silicon layer and the transparent electrode as well as the design of the photonic crystal structure (nanohole array) with the stop band in the lateral direction and the emission cone in the perpendicular direction. The top electrodes, also to be patterned into an array of macroscopic sizes, would allow selective pumping of individual SPS zones so as to allow selection of single-photon emitters that are brightest, monochromatic and yet still satisfy the single-photon criterion. These measures are expected to provide us the first-ever, arrayed, electrically-pumped, monochromatic silicon single-photon sources in the telecom O-band that are compatible to and ready for integration with silicon electronics for quantum information processing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.