Black Phosphorus–Monolayer MoS₂ van der Waals Heterojunction p–n Diode

Abstract

Phosphorene, an elemental 2D material, which is the monolayer of black phosphorus, has been mechanically exfoliated recently. In its bulk form, black phosphorus shows high carrier mobility (~10000 cm 2 /V· s) and a ~0.3 eV direct bandgap. Well-behaved p-type field-effect transistors with mobilities of up to 1000 cm 2 /V· s, as well as phototransistors, have been demonstrated on few-layer black phosphorus, showing its promise for electronics and optoelectronics applications due to its high hole mobility and thickness-dependence direct bandgap. However, p-n junctions, the basic building blocks of modern electronic and optoelectronic devices, have not yet been realized based on black phosphorus. In this paper, we demonstrate a gate tunable p-n diode based on a p-type black phosphorus/n-type monolayer MoS2 van der Waals p-n heterojunction. Upon illumination, these ultra-thin p-n diodes show a maximum photodetection responsivity of 418 mA/W at the wavelength of 633 nm, and photovoltaic energy conversion with an external quantum efficiency of 0.3%. These p-n diodes show promise for broadband photodetection and solar energy harvesting.Key words: black phosphorus, phosphorene, MoS2, p-n diode, van der Waals heterojunction, photodetection, solar cell 3 The successful isolation of graphene from graphite has led to its extensive study in physics, materials, and nano-engineering due to its extraordinary electrical and mechanical properties. [1][2][3][4] However, a lack of a bandgap limits its potential for electronic device applications, and has inspired the exploration of other 2D layered materials. [5][6][7] Among them, transition metal dichalcogenides (TMDCs), such as MoS2, are the most studied materials. [8][9][10][11] Recently, phosphorene, the monolayer form of black phosphorus, has been successfully isolated. 12 Analogous to graphite and graphene, black phosphorus is a stack of phosphorene monolayers, bound together by van der Waals interactions. 12,13 Bulk black phosphorus shows a ~0.3 eV direct bandgap and a mobility of up to ~10000 cm 2 /V· s. 14-17 Its bandgap increases as its thickness decreases, and is predicted to have a >1 eV direct bandgap in its monolayer form. 12,13 Well-behaved p-type field-effect transistors with mobilities of up to 1000 cm 2 /V· s, as well as inverters, have been demonstrated on few-layer black phosphorus. 12,13,[18][19][20] Based on its direct bandgap, few-layer black phosphorus phototransistors have been demonstrated with a responsivity of 4.8 mA/W. 19 These results indicate that black phosphorus is a promising candidate for both high performance electronics and optoelectronics applications due to its ultra-thin 2D nature, high hole mobility, and narrower direct bandgap compared to most of TMDCs. P-N junctions are the basic building blocks of modern semiconductor devices, including diodes, bipolar transistors, photodiodes, light-emitting diodes, and solar cells. In the conventional p-n homo-junction, the p-and n-type regions are formed by 4 chemically doping a bulk semiconduct...

Booming Development of Group IV–VI Semiconductors: Fresh Blood of 2D Family

“…Van der Waals (vdW) heterostructures composed of 2D layered materials have been attempted intensively recently due to the novel physical properties covering a wide range of electronic, optical, and optoelectronic systems 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242. Jo and co‐workers130 synthesized polymorphic 2D tin‐sulfides of either p‐type SnS or n‐type SnS 2 via adjusting hydrogen during the process.…”

“…The drain–source current is controlled by the gate voltage on the dielectric layer. High carrier mobility, high switching ratio and low subthreshold swing means high performance FET, which depends on the metal contacts,247 channel materials (thickness,248, 249 doping,192, 250, 251, 252, 253, 254 heterostructures200, 208), dielectric materials (back‐gate,86, 255 top‐gate,256 liquid gate257), and so forth. 2D GIVMCs based FETs have demonstrated exciting performance.…”

Emerging Trends in Phosphorene Fabrication towards Next Generation Devices

“…The monolayer of BP, known as phosphorene, exhibits physical properties that can be significantly different from those of its bulk counterpart 16. Phosphorene has changed the landscape of many research areas in science and technology, particularly in condensed matter physics, and it has received much attention recently for its use as the base component of novel nanodevices, e.g., transistors, nanomechanical resonators, photovoltaics, photodetectors, batteries and sensors 9, 10, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37…”

Ultrahigh, Ultrafast, and Self‐Powered Visible‐Near‐Infrared Optical Position‐Sensitive Detector Based on a CVD‐Prepared Vertically Standing Few‐Layer MoS2/Si Heterojunction

“…However, pure MoS 2 ‐based optoelectronic devices are usually limited to infrared light detection and lower photoelectric conversion efficiency (PCE) because of the direct band gap of 1.8 eV for single‐layered MoS 2 sheet5, 6 and the picosecond ultrashort carrier lifetime 13, 14. To conquer the drawbacks of wavelength and lifetime limitations, van der Waals heterostructures,15 or lateral heterostructures,16, 17 which are made by stacking a monolayer on the top of another monolayer or a few‐layer crystal or controlled by epitaxial growth of lateral heterojunction, are developed and show great potential for designing high‐performance 2D material‐based photodetectors owing to the combined advantages and synergetic effects of different 2D materials with various band gaps and work functions,18, 19, 20 and the ultrafast layer‐to‐layer transfer speed of carriers 21. To date, various van der Waals heterostructures and lateral heterostructures have been prepared and successfully applied in photodetectors,17, 22 field‐effect transistors,23 photocatalysts,24 and solar cells 16, 25.…”