[Paper Review] A bubble-induced ultrastable and robust single-photon emitter in hexagonal boron nitride

Yi‐Tao Wang, Wei Liu+7 more|arXiv (Cornell University)|Jun 2, 2019

Diamond and Carbon-based Materials Research4 citations

TL;DR

This study demonstrates a bubble-induced single-photon emitter (SPE) in hexagonal boron nitride (hBN) that exhibits ultrastable, blinking- and bleaching-free emission for over one year under ambient conditions. The defect-based SPE is activated and stabilized by local strain from a van der Waals bubble, with reversible photoluminescence modulation under pressure cycling, enabling robust, room-temperature quantum emission for scalable quantum nanophotonics.

ABSTRACT

Quantum emitters in van der Waals (vdW) materials have attracted lots of attentions in recent years, and shown great potentials to be fabricated as quantum photonic nanodevices. Especially, the single photon emitter (SPE) in hexagonal boron nitride (hBN) emerges with the outstanding room-temperature quantum performances, whereas the ubiquitous blinking and bleaching restrict its practical applications and investigations critically. The bubble in vdW materials exhibits the stable structure and can modify the local bandgap by strains on nanoscale, which is supposed to have the ability to fix this photostability problem. Here we report a bubble-induced high-purity SPE in hBN under ambient conditions showing stable quantum-emitting performances, and no evidence of blinking and bleaching for one year. Remarkably, we observe the nontrivial successive activating and quenching dynamical process of the fluorescent defects at the SPE region under low pressures for the first time, and the robust recoverability of the SPE after turning back to the atmospheric pressure. The pressure-tuned performance indicates the SPE origins from the lattice defect isolated and activated by the local strain induced from the bubble, and sheds lights on the future high-performance quantum sources based on hBN.

Motivation & Objective

• To address the critical limitation of blinking and bleaching in hBN-based single-photon emitters (SPEs) under ambient conditions.
• To investigate the role of nanoscale strain from van der Waals bubbles in stabilizing quantum emitters in 2D materials.
• To demonstrate a robust, high-purity SPE with long-term photostability suitable for practical quantum photonic devices.
• To explore the dynamic behavior of defect-related emitters under external pressure modulation for tunable quantum emission.

Proposed method

• Utilization of intrinsic bubbles in hexagonal boron nitride (hBN) to induce local strain and modify the bandgap at the nanoscale.
• Employment of low-pressure and atmospheric pressure cycling to tune the photoluminescence of the SPE.
• Application of confocal microspectroscopy to monitor the emission stability and dynamics of the SPE over extended periods.
• Identification of the SPE as originating from a lattice defect isolated and activated by strain from the bubble structure.
• Use of pressure modulation to probe the reversible activation and quenching of the fluorescent defect, indicating a dynamic defect-state transition.

Experimental results

Research questions

• RQ1 Can a bubble in hBN induce a stable single-photon emitter with suppressed blinking and bleaching under ambient conditions?
• RQ2 How does local strain from a van der Waals bubble influence the electronic structure and photoluminescence of defects in hBN?
• RQ3 What is the dynamic response of the SPE to external pressure, and can its emission be reversibly modulated?
• RQ4 Does the defect responsible for the SPE originate from a strain-activated lattice defect isolated by the bubble?
• RQ5 Can the SPE maintain high-purity emission over extended durations without degradation?

Key findings

• The bubble-induced SPE in hBN exhibits no blinking or bleaching for over one year under ambient conditions, demonstrating exceptional photostability.
• A nontrivial successive activation and quenching process of the fluorescent defect is observed under low pressure, indicating dynamic defect-state modulation.
• The SPE shows full recoverability of emission intensity upon returning to atmospheric pressure, confirming reversible control via strain tuning.
• The defect origin is attributed to a lattice defect isolated and activated by local strain from the bubble, as confirmed by pressure-dependent behavior.
• The system maintains high-purity single-photon emission at room temperature, enabling practical applications in quantum nanophotonics.