Ferroelectric WS2 Quantum Emitter Modulation for Higher Photon Purity
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Solution Overview
Problem
Current quantum emitters face challenges in achieving high single photon emission purity due to the emission of semi-classical light from defect-bound excitons, which is spectrally degenerate with quantum light and cannot be easily filtered out.
Innovation Solution
The introduction of a ferroelectric layer adjacent to the quantum emitter in a monolayer WS2 film, allowing for the modulation of single photon emission purity by reversing the ferroelectric polarization, thereby switching between quantum and semi-classical emission regimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum emitters are used in monolayer WS2, then single photon emission can be achieved, but semi-classical light from defect-bound excitons contaminates the emission and reduces purity
Solution Approach 1:
A ferroelectric layer is introduced as an intermediary between the quantum emitter in monolayer WS2 and the substrate. This ferroelectric layer mediates the interaction by providing switchable electric field effects that selectively enhance quantum light emission while suppressing semi-classical light from defect-bound excitons, thereby resolving the contamination issue without modifying the quantum emitter itself
Solution Approach 2:
The invention changes the electric field parameter by switching the polarization state of the ferroelectric layer. By applying external electric fields or voltage, the ferroelectric polarization can be reversed between up and down states, which dynamically modulates the emission characteristics and filters out semi-classical light, thereby improving single photon emission purity
2Reliability
If ferroelectric polarization is reversed to modulate emission purity, then single photon emission purity is improved, but device complexity increases
Solution Approach 1:
The ferroelectric layer serves multiple functions simultaneously: it acts as a substrate for the monolayer WS2, provides switchable electric field effects for emission modulation, and enables nonvolatile memory functionality through polarization retention. This multi-functionality reduces the need for additional separate components, thereby mitigating the increase in device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables nonvolatile modulation of single photon emission purity, achieving up to 94% purity by controlling the ferroelectric polarization, which is the highest reported purity for WS2 single photon emitters.
Implementation Method 1
The introduction of a ferroelectric layer adjacent to the quantum emitter in a monolayer WS2 film, allowing for the modulation of single photon emission purity by reversing the ferroelectric polarization
Implementation Method 2
ferroelectric modulation of quantum emitters
Data Source
AI summary
A single photon emitter having a ferroelectric film on a substrate, a monolayer or thin film formed on the ferroelectric where the monolayer or thin film contains a single photon emitter, a conductive contact layer formed over a portion of the monolayer or thin film, and an electrical contact adapted to selectively apply a bias voltage to the conductive layer. The ferroelectric film may comprise poly (vinylidene fluoride-co-trifluoroethylene). The monolayer or thin film formed on the ferroelectric may comprise WS2. Also disclosed is the related method of forming a single photon emitter.