Heterostructures comprising two-dimensional (2D) semiconductors fabricated by individual stacking exhibit interesting characteristics owing to their 2D nature and atomically sharp interface. As an emerging 2D material, black phosphorus (BP) nanosheets have drawn much attention because of their small band gap semiconductor characteristics along with high mobility. Stacking structures composed of p-type BP and n-type transition metal dichalcogenides can produce an atomically sharp interface with van der Waals interaction which leads to p-n diode functionality. In this study, for the first time, we fabricated a heterojunction p-n diode composed of BP and WS. The rectification effects are examined for monolayer, bilayer, trilayer, and multilayer WS flakes in our BP/WS van der Waals heterojunction diodes and also verified by density function theory calculations. We report superior functionalities as compared to other van der Waals heterojunction, such as efficient gate-dependent static rectification of 2.6 × 10, temperature dependence, thickness dependence of rectification, and ideality factor of the device. The temperature dependence of Zener breakdown voltage and avalanche breakdown voltage were analyzed in the same device. Additionally, superior optoelectronic characteristics such as photoresponsivity of 500 mA/W and external quantum efficiency of 103% are achieved in the BP/WS van der Waals p-n diode, which is unprecedented for BP/transition metal dichalcogenides heterostructures. The BP/WS van der Waals p-n diodes have a profound potential to fabricate rectifiers, solar cells, and photovoltaic diodes in 2D semiconductor electronics and optoelectronics.
Recently, van der Waals heterostructures (vdWHs) based on transition‐metal dichalcogenides (TMDs) have attracted significant attention owing to their superior capabilities and multiple functionalities. Herein, a novel vdWH field‐effect transistor (FET) composed of molybdenum ditelluride (MoTe2) and palladium diselenide (PdSe2) is studied for highly sensitive photodetection performance in the broad visible and near‐infrared (VNIR) region. A high rectification ratio of 6.3 × 105 is obtained, stemming from the sharp interface and low Schottky barriers of the MoTe2/PdSe2 vdWHs. It is also successfully demonstrated that the vdWH FET exhibits highly sensitive photo‐detecting abilities, such as noticeably high photoresponsivity (1.24 × 105 A W−1), specific detectivity (2.42 × 1014 Jones), and good external quantum efficiency (3.5 × 106), not only due to the intra‐TMD band‐to‐band transition but also due to the inter‐TMD charge transfer (CT) transition. Further, rapid rise (16.1 µs) and decay (31.1 µs) times are obtained under incident light with a wavelength of 2000 nm due to the CT transition, representing an outcome one order of magnitude faster than values currently in the literature. Such TMD‐based vdWH FETs would improve the photo‐gating characteristics and provide a platform for the realization of a highly sensitive photodetector in the broad VNIR region.
Van
der Waals heterostructures composed of transition-metal dichalcogenide
(TMD) materials have become a remarkable compact system that could
offer an innovative architecture for advanced engineering in high-performance
energy-harvesting and optoelectronic devices. Here, we report a novel
van der Waals (vdW) TMD heterojunction photodiode composed of black
phosphorus (p-BP) and palladium diselenide (n-PdSe2), which
establish a high and tunable rectification and photoresponsivity.
A high rectification up to ≈7.1 × 105 is achieved,
which is successfully tuned by employing the back-gate voltage to
the heterostructure devices. Besides, the device significantly shows
the high and gate-controlled photoresponsivity of R = 9.6 × 105, 4.53 × 105 and 1.63
× 105 A W–1 under the influence
of light of different wavelengths (λ = 532, 1064, and 1310 nm)
in visible and near-infrared regions, respectively, because of interlayer
optical transition and low Schottky. The device also demonstrates
extraordinary values of detectivity (D = 5.8 ×
1013 Jones) and external quantum efficiency (EQE ≈
9.4 × 106), which are an order of magnitude higher
than the currently reported values. The effective enhancement of photovoltaic
characteristics in visible and infrared regions of this TMD heterostructure-based
system has a huge potential in the field of optoelectronics to realize
high-performance infrared photodetectors.
The BP/h-BN/ReSe2 heterostructure demonstrates the highest tunneling-based rectification ratio and responsivity. The tunneling device operates in switching operation at up to GHz frequency.
There have been a few studies of
heterojunctions composed of two-dimensional
transition-metal dichalcogenides (TMDs) and an oxide layer, but such
studies of high-performance electric and optoelectronic devices are
essential. Such heterojunctions with low-resistivity metal contacts
are needed by the electronics industry to fabricate efficient diodes
and photovoltaic devices. Here, a van der Waals heterojunction composed
of p-type black phosphorus (p-BP) and n-type indium–gallium–zinc
oxide (n-IGZO) films with low-resistivity metal contacts is reported,
and it demonstrates high rectification. The low off-state leakage
current in the thick IGZO film accounts for the high rectification
ratio in a sharp interface of p-BP/n-IGZO devices. For electrostatic
gate control, an ionic liquid is introduced to achieve a high rectification
ratio of 9.1 × 104. The photovoltaic measurements
of p-BP/n-IGZO show fast rise and decay times, significant open-circuit
voltage and short-circuit current, and a high photoresponsivity of
418 mA/W with a substantial external quantum efficiency of 12.1%.
The electric and optoelectronic characteristics of TMDs/oxide layer
van der Waals heterojunctions are attractive for industrial applications
in the near future.
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