Strain tunable quantum dot based non-classical photon sources

Abstract

Semiconductor quantum dots are leading candidates for the on-demand generation of single photons and entangled photon pairs. High photon quality and indistinguishability of photons from different sources are critical for quantum information applications. The inability to grow perfectly identical quantum dots with ideal optical properties necessitates the application of post-growth tuning techniques via e.g. temperature, electric, magnetic or strain fields. In this review, we summarize the state-of-the-art and highlight the advantages of strain tunable non-classical photon sources based on epitaxial quantum dots. Using piezoelectric crystals like PMN-PT, the wavelength of single photons and entangled photon pairs emitted by InGaAs/GaAs quantum dots can be tuned reversibly. Combining with quantum light-emitting diodes simultaneously allows for electrical triggering and the tuning of wavelength or exciton fine structure. Emission from light hole exciton can be tuned, and quantum dot containing nanostructure such as nanowires have been piezo-integrated. To ensure the indistinguishability of photons from distant emitters, the wavelength drift caused by piezo creep can be compensated by frequency feedback, which is verified by two-photon interference with photons from two stabilized sources. Therefore, strain tuning proves to be a flexible and reliable tool for the development of scalable quantum dots-based non-classical photon sources.

Spin-splitting and switchable half-metallicity in a van der Waals multiferroic CuBiP2Se6/GdClBr heterojunction

“…In experiments, such as achieving a tensile biaxial strain of 6%, in-plane biaxial strain is generated by applying a certain voltage to the piezoelectric ceramic substrate. 69 In addition, by using substrates with different lattice mismatches, a tensile biaxial strain of 6% can be achieved. Due to the lattice mismatch of the heterojunction being only 0.11%, applying biaxial strain to the heterojunction is equivalent to applying biaxial strain to the two monolayers, respectively.…”

Chip-Scale Quantum Emitters

“…In addition, a discussion of the prospects and challenges of deploying the strain engineering technique for future scalable quantum networks and photonic quantum circuits was also presented. Yang and co-workers [51] emphasized that inability to grow perfectly identical quantum dots with ideal optical properties necessitates the application of post-growth tuning techniques via, e.g., temperature, electric, magnetic, or strain fields. They showed that the wavelength of single photons and entangled photon pairs emitted by InGaAs/GaAs quantum dots can be reversibly tuned using piezoelectric crystals such as PMN-PT [51].…”

“…Yang and co-workers [51] emphasized that inability to grow perfectly identical quantum dots with ideal optical properties necessitates the application of post-growth tuning techniques via, e.g., temperature, electric, magnetic, or strain fields. They showed that the wavelength of single photons and entangled photon pairs emitted by InGaAs/GaAs quantum dots can be reversibly tuned using piezoelectric crystals such as PMN-PT [51]. For electrical triggering and tuning of the wavelength or the exciton's fine structure, they used quantum light-emitting diodes.…”

“…For electrical triggering and tuning of the wavelength or the exciton's fine structure, they used quantum light-emitting diodes. Furthermore, the frequency even feedback, which is verified by two-photon interference with photons from two stabilized sources, was employed to compensate the wavelength drift caused by piezo creep and also to ensure the indistinguishability of photons [51]. Nevertheless, by performing many attempts to prepare a GaAs quantum dot single-photon source on the chip scale, considerable progress was also made in the preparation of III-nitride QDs that can even operate at room temperature.…”

Light-hole states in a strained quantum dot: numerical calculation and phenomenological models

“…It has been known for some time now that the fine structure splitting of the HH exciton can be changed, and even made to vanish, by applying an in-plane stress [56]; a model evaluating the effect of the Bir and Pikus Hamiltonian on the electron-heavy hole exchange has been proposed in Ref. [57].…”