Investigation of band-offsets at monolayer-multilayer MoS₂ junctions by scanning photocurrent microscopy.

  title={Investigation of band-offsets at monolayer-multilayer MoS₂ junctions by scanning photocurrent microscopy.},
  author={Sarah L. Howell and Deep Jariwala and Chung-Chiang Wu and Kan Sheng Chen and Vinod Kumar Sangwan and Junmo Kang and Tobin J. Marks and Mark Christopher Hersam and Lincoln J. Lauhon},
  journal={Nano letters},
  volume={15 4},
The thickness-dependent band structure of MoS2 implies that discontinuities in energy bands exist at the interface of monolayer (1L) and multilayer (ML) thin films. The characteristics of such heterojunctions are analyzed here using current versus voltage measurements, scanning photocurrent microscopy, and finite element simulations of charge carrier transport. Rectifying I-V curves are consistently observed between contacts on opposite sides of 1L/ML junctions, and a strong bias-dependent… 

Figures from this paper

Enhanced conductivity along lateral homojunction interfaces of atomically thin semiconductors

Energy band realignment at the interfaces between materials in heterostructures can give rise to unique electronic characteristics and non-trivial low-dimensional charge states. In a homojunction of

On the Use of Photocurrent Imaging To Determine Carrier Diffusion Lengths in Nanostructured Thin-Film Field-Effect Transistors

Scanning photocurrent microscopy (SPCM) has been widely used as a powerful experimental technique to investigate charge transport and recombination in nanostructured field-effect transistors (FETs).

MoS 2 Heterojunctions by Thickness

In this work, we report lateral heterojunction formation in as-exfoliated MoS2 flakes by thickness modulation. Kelvin probe force microscopy is used to map the surface potential at the

MoS2 Heterojunctions by Thickness Modulation

Experimental and theoretical understanding of the band alignment and photoresponse of thickness modulated MoS2 junctions with important implications for exploring novel optoelectronic devices are presented.

Phonon-assisted carrier transport through a lattice-mismatched interface

MoS2 typically exhibits unconventional layer-thickness-dependent electronic properties. It also exhibits layer-dependent band structures including indirect-to-direct band transitions, owing to which

UC Office of the President Recent Work Title On the use of photocurrent imaging to determine carrier diffusion lengths in nanostructured thin-film field-effect transistors

Scanning photocurrent microscopy (SPCM) has been widely used as a powerful experimental technique to investigate charge transport and recombination in nanostructured field-effect transistors (FETs).

Spatiotemporal Imaging of Thickness-Induced Band-Bending Junctions.

A new type of homojunction termed a "band-bending junction" whose potential landscape depends solely on the difference in thickness between the two sides of the junction is reported, which may enable new optoelectronic devices that rely solely on band bending arising from thickness variations to separate charge carriers.

Sub-bandgap response of graphene/SiC Schottky emitter bipolar phototransistor examined by scanning photocurrent microscopy

Graphene layers grown epitaxially on SiC substrates are attractive for a variety of sensing and optoelectronic applications because the graphene acts as a transparent, conductive, and chemically

Intrinsic Transport in 2D Heterostructures Mediated through h-BN Tunneling Contacts.

This work applies the recently reported hexagonal boron nitride (h-BN) tunnel contact scheme to probe the junction characteristics of a lateral TMD heterostructure grown via chemical vapor deposition and finds that both the photovoltaic as well as hot carrier generation effects are dominant mechanisms driving photoresponse, depending on the external biasing conditions.



Barrier height measurement of metal contacts to Si nanowires using internal photoemission of hot carriers.

The combined tomography, electrical characterization, and numerical modeling approach represents a significant advance in the quantitative analysis of transport mechanisms at nanoscale interfaces that can be extended to other nanoscales devices and heterostructures.

Elucidating the Photoresponse of Ultrathin MoS2 Field-Effect Transistors by Scanning Photocurrent Microscopy

The mechanisms underlying the intrinsic photoresponse of few-layer (FL) molybdenum disulfide (MoS2) field-effect transistors are investigated via scanning photocurrent microscopy. We attribute the

Electron-hole transport and photovoltaic effect in gated MoS2 Schottky junctions

It is shown that a multi-layer MoS2 channel can be hole-doped by palladium contacts, yielding MoS1 p-type transistors and when two different materials are used for the source and drain contacts, the Schottky junctions formed at theMoS2 contacts produce a clear photovoltaic effect.

Band lineup of layered semiconductor heterointerfaces prepared by van der Waals epitaxy: Charge transfer correction term for the electron affinity rule

The occurrence of quantum dipoles at layered materials semiconductor heterointerfaces was investigated by photoemission spectroscopy (PES). Due to the unique properties of layered compounds the

Nature of electronic states in atomically thin MoS₂ field-effect transistors.

It is suggested that Coulomb potential from trapped charges in the substrate is the dominant source of disorder in MoS(2) field-effect devices, which leads to carrier localization, as well, in low-temperature electrical transport experiments.

Atomically thin MoS₂: a new direct-gap semiconductor.

The electronic properties of ultrathin crystals of molybdenum disulfide consisting of N=1,2,…,6 S-Mo-S monolayers have been investigated by optical spectroscopy and the effect of quantum confinement on the material's electronic structure is traced.

Large and tunable photothermoelectric effect in single-layer MoS2.

A large and tunable Seebeck coefficient of the single-layer MoS(2) paves the way to new applications of this material such as on-chip thermopower generation and waste thermal energy harvesting.

Lateral heterojunctions within monolayer semiconductors

Heterojunctions between three-dimensional (3D) semiconductors with different bandgaps are the basis of modern light-emitting diodes, diode lasers, and high-speed transistors. Creating analogous

Layer-by-layer thinning of MoS2 by plasma.

The electronic structures of two-dimensional materials are strongly dependent on their thicknesses; for example, there is an indirect to direct band gap transition from multilayer to single-layer

Hot Carrier–Assisted Intrinsic Photoresponse in Graphene

The intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices is reported, providing strong evidence that nonlocal hot carrier transport, rather than the photovoltaic effect, dominates the intrinsic photoresponse in graphene.