Gate Tunable Quantum Oscillations in Air-Stable and High Mobility Few-Layer Phosphorene Heterostructures (1412.0717v2)

Abstract: As the only non-carbon elemental layered allotrope, few-layer black phosphorus or phosphorene has emerged as a novel two-dimensional (2D) semiconductor with both high bulk mobility and a band gap. Here we report fabrication and transport measurements of phosphorene-hexagonal BN (hBN) heterostructures with one-dimensional (1D) edge contacts. These transistors are stable in ambient conditions for >300 hours, and display ambipolar behavior, a gate-dependent metal-insulator transition, and mobility up to 4000 $cm^2$/Vs. At low temperatures, we observe gate-tunable Shubnikov de Haas (SdH) magneto-oscillations and Zeeman splitting in magnetic field with an estimated g-factor ~2. The cyclotron mass of few-layer phosphorene holes is determined to increase from 0.25 to 0.31 $m_e$ as the Fermi level moves towards the valence band edge. Our results underscore the potential of few-layer phosphorene (FLP) as both a platform for novel 2D physics and an electronic material for semiconductor applications.

• The paper reveals gate-tunable Shubnikov de Haas oscillations in phosphorene devices, with mobility rising from ~400 cm²/Vs at room temperature to ~4000 cm²/Vs at low temperatures.
• It details the fabrication of air-stable phosphorene-hBN heterostructures featuring over 300 hours of ambient stability and tunable metal-insulator transitions.
• The paper identifies Zeeman splitting above 8T with an inferred g-factor of approximately 2, corroborated by cyclotron mass measurements and ab initio calculations.

Overview of Gate Tunable Quantum Oscillations in Few-Layer Phosphorene Heterostructures

This paper explores the properties of few-layer phosphorene heterostructures, emphasizing their potential for high mobility and air-stability in electronic applications. As the first known stable elemental layered allotrope apart from carbon, phosphorene, derived from black phosphorus, offers both a band gap and remarkable electronic mobility. These characteristics set the stage for innovative explorations in two-dimensional (2D) semiconductor physics and technology.

Fabrication and Stability

The authors detail the fabrication of phosphorene-hexagonal boron nitride (hBN) heterostructures using 1D edge contacts to ensure stability. These constructs exhibit ambient stability for over 300 hours and deploy as field-effect transistors showcasing ambipolar behavior and a gate-dependent metal-insulator transition. At room temperature, the devices reach a mobility of ~400 cm$^2$/Vs, which notably increases to ~4000 cm$^2$/Vs at low temperatures, on par with or surpassing other 2D materials like graphene.

Quantum Transport Phenomena

Gate-tunable Shubnikov de Haas (SdH) oscillations, indicative of quantum transport phenomena, are observed in these phosphorene devices under magnetic fields above 3.5T. The paper meticulously estimates the cyclotron mass of holes, noting a variance between 0.25 and 0.31 $m_e$ as the Fermi level approaches the valence band edge. These measurements align with ab initio calculations, solidifying phosphorene's promise as a high-mobility electronic material.

Zeeman Splitting and g-factor

The resonance doubling at higher magnetic fields (>8T) marks the emergence of Zeeman splitting, from which a g-factor of approximately 2 is inferred. This finding further complements the suite of magnetotransport phenomena accessible in phosphorene, broadening the understanding of its characteristics as a semiconducting material.

Potential and Future Prospects

The paper highlights few-layer phosphorene's capability as a flexible platform in quantum transport, making it attractive for next-generation electronics and optoelectronics. The stability advancements via hBN encapsulation extend possibilities for handling other sensitive 2D materials. Moreover, the observed metal-insulator transitions, anisotropic transport properties, and effective mass variations underline phosphorene's potential as a model material for exploring novel electron behaviors and developing transformative electronic, thermal, and photonic devices.

Conclusion

This work illustrates significant progress in engineering stable, high-mobility phosphorene devices for practical applications while offering insights into the material's fundamental physics. It opens pathways for further exploration of 2D semiconductors under varied conditions, promising considerable advancements in electronic components and theoretical models. Future work may accentuate phosphorene's unique properties and its efficiency in various temperature and doping regimes, fostering innovations in device design and functionality.