scholarly journals Gate-tunable photodetector and ambipolar transistor implemented using a graphene/MoSe2 barristor

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Gwangtaek Oh ◽  
Ji Hoon Jeon ◽  
Young Chul Kim ◽  
Yeong Hwan Ahn ◽  
Bae Ho Park
Keyword(s):  
Gate Dielectric ◽  
Transition Metal Dichalcogenides ◽  
External Bias ◽  
High K ◽  
Ambipolar Behavior ◽  
Tuning Ratio ◽  
Metal Dichalcogenides ◽  
Lower Mobility ◽  
High Carrier Mobility ◽  
High Carrier

AbstractNext-generation electronic and optoelectronic devices require a high-quality channel layer. Graphene is a good candidate because of its high carrier mobility and unique ambipolar transport characteristics. However, the on/off ratio and photoresponsivity of graphene are typically low. Transition metal dichalcogenides (e.g., MoSe2) are semiconductors with high photoresponsivity but lower mobility than that of graphene. Here, we propose a graphene/MoSe2 barristor with a high-k ion-gel gate dielectric. It shows a high on/off ratio (3.3 × 104) and ambipolar behavior that is controlled by an external bias. The barristor exhibits very high external quantum efficiency (EQE, 66.3%) and photoresponsivity (285.0 mA/W). We demonstrate that an electric field applied to the gate electrode substantially modulates the photocurrent of the barristor, resulting in a high gate tuning ratio (1.50 μA/V). Therefore, this barristor shows potential for use as an ambipolar transistor with a high on/off ratio and a gate-tunable photodetector with a high EQE and responsivity.

scholarly journals Charge Transfer from Lead Sulfide Quantum Dots to MoS-=SUB=-2-=/SUB=- Nanoplatelets-=SUP=-*-=/SUP=-

2020 ◽  
Vol 128 (8) ◽  
pp. 1193
Author(s):  
I.D. Skurlov ◽  
A.S. Mudrak ◽  
A.V. Sokolova ◽  
S.A. Cherevkov ◽  
M.A. Baranov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Charge Transfer ◽  
Transition Metal ◽  
Lead Sulfide ◽  
Transition Metal Dichalcogenides ◽  
Order Of Magnitude ◽  
Metal Dichalcogenides ◽  
High Carrier Mobility ◽  
High Carrier ◽  
Lead Sulfide Quantum Dots

The research interest in the transition metal dichalcogenides (TMD) has been reborn a few years ago. This had happened due to the remarkable properties of monolayered TMD (e. g. high carrier mobility and high exciton binding energy) and due to the development of the exfoliation methods. Photoconductive MoS2-based devices spectral range can be expanded to the NIR by coupling them with PbS QDs. However, this requires extensive knowledge about the the charge and energy transfer processes in such systems. In this paper, we investigate charge transfer between PbS QDs and MoS2 nanoplatelets (NPls). Using the PL decay analysis, we show how the charge transfer efficiency changes with the distance between the QDs and NPls, as well as with QD size. Last, we demonstrate that the addition of the MoS2 NPLs increases the photoconductive response for up to an order of magnitude, as compared to the bare QD. Keywords: transition metal dichalcogenides, quantum dots, charge transfer, lead sulfide, molybdenum disulfide.

scholarly journals High carrier mobility of CoPc wires based field-effect transistors using bi-layer gate dielectric

AIP Advances ◽  
2013 ◽  
Vol 3 (11) ◽  
pp. 112123 ◽  
Author(s):  
Murali Gedda ◽  
Nimmakayala V. V. Subbarao ◽  
Sk. Md. Obaidulla ◽  
Dipak K. Goswami
Keyword(s):  
Field Effect ◽  
Carrier Mobility ◽  
Gate Dielectric ◽  
Field Effect Transistors ◽  
High Carrier Mobility ◽  
High Carrier

scholarly journals Ionic-Liquid Gating in Two-Dimensional TMDs: The Operation Principles and Spectroscopic Capabilities

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1576
Author(s):  
Daniel Vaquero ◽  
Vito Clericò ◽  
Juan Salvador-Sánchez ◽  
Jorge Quereda ◽  
Enrique Diez ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Band Gap ◽  
Field Effect Transistors ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Spectroscopy Technique ◽  
Promising Technique ◽  
Transfer Characteristics ◽  
Ambipolar Behavior ◽  
Metal Dichalcogenides

Ionic-liquid gating (ILG) is able to enhance carrier densities well above the achievable values in traditional field-effect transistors (FETs), revealing it to be a promising technique for exploring the electronic phases of materials in extreme doping regimes. Due to their chemical stability, transition metal dichalcogenides (TMDs) are ideal candidates to produce ionic-liquid-gated FETs. Furthermore, as recently discovered, ILG can be used to obtain the band gap of two-dimensional semiconductors directly from the simple transfer characteristics. In this work, we present an overview of the operation principles of ionic liquid gating in TMD-based transistors, establishing the importance of the reference voltage to obtain hysteresis-free transfer characteristics, and hence, precisely determine the band gap. We produced ILG-based bilayer WSe2 FETs and demonstrated their ambipolar behavior. We estimated the band gap directly from the transfer characteristics, demonstrating the potential of ILG as a spectroscopy technique.

Novel two-dimensional β-GeSe and β-SnSe semiconductors: anisotropic high carrier mobility and excellent photocatalytic water splitting

2020 ◽  
Vol 8 (37) ◽  
pp. 19612-19622 ◽  
Author(s):  
Yuanfeng Xu ◽  
Ke Xu ◽  
Congcong Ma ◽  
Ying Chen ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Carrier Mobility ◽  
Photocatalytic Reaction ◽  
Two Dimensional ◽  
Photocatalytic Water Splitting ◽  
External Bias ◽  
High Carrier Mobility ◽  
High Carrier

Monolayer β-GeSe and β-SnSe are promising candidates for electrocatalysts which need ultralow external bias to drive the whole photocatalytic reaction.

High-k Gate Dielectrics on Silicon and Germanium: Impact of Surface Preparation

2005 ◽  
Vol 103-104 ◽  
pp. 3-6 ◽  
Author(s):  
Alessio Beverina ◽  
M.M. Frank ◽  
H. Shang ◽  
S. Rivillon ◽  
F. Amy ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Gate Dielectrics ◽  
Surface Preparation ◽  
Semiconductor Surface ◽  
High K ◽  
Prime Concern ◽  
High Carrier Mobility ◽  
High Carrier ◽  
Silicon And Germanium ◽  
The Impact

We review the impact of semiconductor surface preparation on the performance of metal-oxidesemiconductor field-effect transistor (MOSFET) gate stacks. We discuss high-permittivity dielectrics such as hafnium oxide and aluminum oxide on silicon and on the high carrier mobility substrate germanium. On Si, scaling of the gate stack is the prime concern. On Ge, fundamental issues of chemical and electrical passivation need to be resolved. Surface treatments considered include oxidation, nitridation, hydrogenation, chlorination, and organic functionalization.

Scalability of MOCVD-deposited Hafnium Oxide

2003 ◽  
Vol 765 ◽  
Author(s):  
S. Van Elshocht ◽  
R. Carter ◽  
M. Caymax ◽  
M. Claes ◽  
T. Conard ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Interfacial Layer ◽  
Gate Dielectric ◽  
Deposition Process ◽  
Oxide Thickness ◽  
Process Conditions ◽  
Primary Concern ◽  
Gate Electrode ◽  
K Value ◽  
High K

AbstractBecause of aggressive downscaling to increase transistor performance, the physical thickness of the SiO2 gate dielectric is rapidly approaching the limit where it will only consist of a few atomic layers. As a consequence, this will result in very high leakage currents due to direct tunneling. To allow further scaling, materials with a k-value higher than SiO2 (“high-k materials”) are explored, such that the thickness of the dielectric can be increased without degrading performance.Based on our experimental results, we discuss the potential of MOCVD-deposited HfO2 to scale to (sub)-1-nm EOTs (Equivalent Oxide Thickness). A primary concern is the interfacial layer that is formed between the Si and the HfO2, during the MOCVD deposition process, for both H-passivated and SiO2-like starting surfaces. This interfacial layer will, because of its lower k-value, significantly contribute to the EOT and reduce the benefit of the high-k material. In addition, we have experienced serious issues integrating HfO2 with a polySi gate electrode at the top interface depending on the process conditions of polySi deposition and activation anneal used. Furthermore, we have determined, based on a thickness series, the k-value for HfO2 deposited at various temperatures and found that the k-value of the HfO2 depends upon the gate electrode deposited on top (polySi or TiN).Based on our observations, the combination of MOCVD HfO2 with a polySi gate electrode will not be able to scale below the 1-nm EOT marker. The use of a metal gate however, does show promise to scale down to very low EOT values.

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