scholarly journals High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Roda Nur ◽  
Takashi Tsuchiya ◽  
Kasidit Toprasertpong ◽  
Kazuya Terabe ◽  
Shinichi Takagi ◽  
...  
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Charge Trapping ◽  
Dual Function ◽  
Light Illumination ◽  
Low Light ◽  
High Responsivity ◽  
Metal Dichalcogenides ◽  
High Resolution Images ◽  
Weak Light ◽  
Light Signals

Abstract2D Transition Metal Dichalcogenides hold a promising potential in future optoelectronic applications due to their high photoresponsivity and tunable band structure for broadband photodetection. In imaging applications, the detection of weak light signals is crucial for creating a better contrast between bright and dark pixels in order to achieve high resolution images. The photogating effect has been previously shown to offer high light sensitivities; however, the key features required to create this as a dominating photoresponse has yet to be discussed. Here, we report high responsivity and high photogain MoS2 phototransistors based on the dual function of HfO2 as a dielectric and charge trapping layer to enhance the photogating effect. As a result, these devices offered a very large responsivity of 1.1 × 106 A W−1, a photogain >109, and a detectivity of 5.6 × 1013 Jones under low light illumination. This work offers a CMOS compatible process and technique to develop highly photosensitive phototransistors for future low-powered imaging applications.

scholarly journals Pure spin photocurrent in non-centrosymmetric crystals: bulk spin photovoltaic effect

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haowei Xu ◽  
Hua Wang ◽  
Jian Zhou ◽  
Ju Li
Keyword(s):  
Mirror Symmetry ◽  
Photovoltaic Effect ◽  
Transition Metal Dichalcogenides ◽  
Spin Current ◽  
Pure Spin ◽  
Light Illumination ◽  
Metal Dichalcogenides ◽  
Critical Components ◽  
Topological Crystalline Insulator

AbstractSpin current generators are critical components for spintronics-based information processing. In this work, we theoretically and computationally investigate the bulk spin photovoltaic (BSPV) effect for creating DC spin current under light illumination. The only requirement for BSPV is inversion symmetry breaking, thus it applies to a broad range of materials and can be readily integrated with existing semiconductor technologies. The BSPV effect is a cousin of the bulk photovoltaic (BPV) effect, whereby a DC charge current is generated under light. Thanks to the different selection rules on spin and charge currents, a pure spin current can be realized if the system possesses mirror symmetry or inversion-mirror symmetry. The mechanism of BSPV and the role of the electronic relaxation time $$\tau$$ τ are also elucidated. We apply our theory to several distinct materials, including monolayer transition metal dichalcogenides, anti-ferromagnetic bilayer MnBi2Te4, and the surface of topological crystalline insulator cubic SnTe.

scholarly journals High-Responsivity Photovoltaic Photodetectors Based on MoTe2/MoSe2 van der Waals Heterojunctions

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 315 ◽  
Author(s):  
Hao Luo ◽  
Bolun Wang ◽  
Enze Wang ◽  
Xuewen Wang ◽  
Yufei Sun ◽  
...  
Keyword(s):  
High Efficiency ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Optoelectronic Devices ◽  
Type Ii ◽  
Zero Bias ◽  
High Responsivity ◽  
Metal Dichalcogenides ◽  
Self Powered ◽  
Ultrafast Charge Transfer

Van der Waals heterojunctions based on transition metal dichalcogenides (TMDs) show promising potential in optoelectronic devices, due to the ultrafast separation of photoexcited carriers and efficient generation of the photocurrent. Herein, this study demonstrated a high-responsivity photovoltaic photodetector based on a MoTe2/MoSe2 type-II heterojunction. Due to the interlayer built-in potential, the MoTe2/MoSe2 heterojunction shows obvious photovoltaic behavior and its photoresponse can be tuned by the gate voltage due to the ultrathin thickness of the heterojunction. This self-powered photovoltaic photodetector exhibits an excellent responsivity of 1.5 A W−1, larger than previously reported TMDs-based photovoltaic photodetectors. Due to the high-efficiency separation of electron-hole pairs and ultrafast charge transfer, the light-induced on/off ratio of current switching is larger than 104 at zero bias, and the dark current is extremely low (~10−13 A). These MoTe2/MoSe2 type-II heterojunctions are expected to provide more opportunities for future nanoscale optoelectronic devices.

Low-light-level three-dimensional video microscope with long working distance objective lenses

1994 ◽  
Vol 52 ◽  
pp. 226-227
Author(s):  
W. Lin ◽  
J. Gregorio ◽  
T.J. Holmes ◽  
D. H. Szarowski ◽  
J.N. Turner
Keyword(s):  
Three Dimensional ◽  
Light Level ◽  
Stereo Pair ◽  
Light Illumination ◽  
Initial Image ◽  
Low Light ◽  
Image Recording ◽  
Depth Discrimination ◽  
Video Microscope ◽  
Working Distance

A low-light level video microscope with long working distance objective lenses has been built as part of our integrated three-dimensional (3-D) light microscopy workstation (Fig. 1). It allows the observation of living specimens under sufficiently low light illumination that no significant photobleaching or alternation of specimen physiology is produced. The improved image quality, depth discrimination and 3-D reconstruction provides a versatile intermediate resolution system that replaces the commonly used dissection microscope for initial image recording and positioning of microelectrodes for neurobiology. A 3-D image is displayed on-line to guide the execution of complex experiments. An image composed of 40 optical sections requires 7 minutes to process and display a stereo pair.The low-light level video microscope utilizes long working distance objective lenses from Mitutoyo (10X, 0.28NA, 37 mm working distance; 20X, 0.42NA, 20 mm working distance; 50X, 0.42NA, 20 mm working distance). They provide enough working distance to allow the placement of microelectrodes in the specimen.

scholarly journals Super-resolved Optical Mapping of Reactive Sulfur-Vacancies in Two-Dimensional Transition Metal Dichalcogenides

ACS Nano ◽  
2021 ◽  
Author(s):  
Miao Zhang ◽  
Martina Lihter ◽  
Tzu-Heng Chen ◽  
Michal Macha ◽  
Archith Rayabharam ◽  
...  
Keyword(s):  
Transition Metal ◽  
Optical Mapping ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Metal Dichalcogenides

Highly electroconductive and uniform WS2 film growth by sulfurization of W film using diethyl sulfide

2021 ◽  
Author(s):  
Yoobeen Lee ◽  
Jin Won Jung ◽  
Jin Seok Lee
Keyword(s):  
Transition Metal ◽  
Grain Boundaries ◽  
High Performance ◽  
Film Growth ◽  
Transition Metal Dichalcogenides ◽  
Electronic Systems ◽  
Intrinsic Defects ◽  
Diethyl Sulfide ◽  
Metal Dichalcogenides

The reduction of intrinsic defects, including vacancies and grain boundaries, remains one of the greatest challenges to produce high-performance transition metal dichalcogenides (TMDCs) electronic systems. A deeper comprehension of the...

Enhanced Photocurrent Response Speed in Charge-Density-Wave Phase of TiSe2-Metal Junctions

Nanoscale ◽  
2021 ◽  
Author(s):  
Thayer Walmsley ◽  
Yaqiong Xu
Keyword(s):  
Carrier Mobility ◽  
Density Wave ◽  
Transition Metal Dichalcogenides ◽  
Response Speed ◽  
Charge Carrier Mobility ◽  
Metal Dichalcogenides ◽  
Charge Density Wave Phase ◽  
Large Sheet ◽  
High Charge Carrier Mobility ◽  
Significant Attention

Group IVB transition metal dichalcogenides (TMDCs) have attracted significant attention due to their predicted high charge carrier mobility, large sheet current density, and enhanced thermoelectric power. Here, we investigate the...

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