High-quality sandwiched black phosphorus heterostructure and its quantum oscillations

Abstract

Two-dimensional materials such as graphene and transition metal dichalcogenides have attracted great attention because of their rich physics and potential applications in next-generation nanoelectronic devices. The family of two-dimensional materials was recently joined by atomically thin black phosphorus which possesses high theoretical mobility and tunable bandgap structure. However, degradation of properties under atmospheric conditions and high-density charge traps in black phosphorus have largely limited its actual mobility thus hindering its future applications. Here, we report the fabrication of stable sandwiched heterostructures by encapsulating atomically thin black phosphorus between hexagonal boron nitride layers to realize ultra-clean interfaces that allow a high field-effect mobility of ∼1,350 cm2V−1 s−1 at room temperature and on–off ratios exceeding 105. At low temperatures, the mobility even reaches ∼2,700 cm2V−1 s−1 and quantum oscillations in black phosphorus two-dimensional hole gas are observed at low magnetic fields. Importantly, the sandwiched heterostructures ensure that the quality of black phosphorus remains high under ambient conditions.

The Critical Role of Substrate in Stabilizing Phosphorene Nanoflake: A Theoretical Exploration

“…Experimentally, phosphorene was found to be able to largely maintain its electronic and Raman characteristics in the h-BN/phosphorene heterostructure [66][67][68][69] . Theoretically, the interaction between BN and monolayer phosphorene was found to be vdW in nature 70,71 .…”

Negative compressibility in graphene-terminated black phosphorus heterostructures

“…Annealing treatments were then conducted on the BN-BP-BN heterostructure at high temperatures up to 500 • C before metal electrode deposition was performed. BN encapsulation and annealing treatment guarantee a clean BN-BP interface with low impurity concentrations [25]. Finally, Cr/Au (2 nm/60 nm) films were deposited to form a top gate and an Ohmic contact with graphene.…”

“…The effects of negative compressibility have been previously observed in ultraclean systems, such as in high-quality LaAlO 3 /SrTiO 3 interfaces [9], two-dimensional (2D) GaAs systems [4,[10][11][12], and ferroelectric materials [13], where Coulomb interactions are normally strong and play an important role in transport properties. Newly emerged 2D layered semiconductors, such as transition-metal dichalcogenides [14][15][16][17][18] and black phosphorus (BP) [19][20][21][22][23][24][25][26][27][28], are new platforms for both nanotechnology and fundamental physics. Among these 2D materials, atomically thin BP is a promising channel material of FETs with high mobility [24][25][26][27] and high stability by encapsulating BP with hexagonal boron nitride (BN) sheets.…”

“…Newly emerged 2D layered semiconductors, such as transition-metal dichalcogenides [14][15][16][17][18] and black phosphorus (BP) [19][20][21][22][23][24][25][26][27][28], are new platforms for both nanotechnology and fundamental physics. Among these 2D materials, atomically thin BP is a promising channel material of FETs with high mobility [24][25][26][27] and high stability by encapsulating BP with hexagonal boron nitride (BN) sheets. Our previous work has found that high-quality BN-BP-BN heterostructures with clean interfaces are ideal 2D electron systems with high mobility [25].…”

“…Among these 2D materials, atomically thin BP is a promising channel material of FETs with high mobility [24][25][26][27] and high stability by encapsulating BP with hexagonal boron nitride (BN) sheets. Our previous work has found that high-quality BN-BP-BN heterostructures with clean interfaces are ideal 2D electron systems with high mobility [25]. High-quality BN-BP-BN heterostructures also offer great opportunities to investigate quantum Hall effects [26], as well as Coulomb interactions of charge carriers in 2D materials.…”