scholarly journals Atomic–layer–confined multiple quantum wells enabled by monolithic bandgap engineering of transition metal dichalcogenides

2021 ◽  
Vol 7 (13) ◽  
pp. eabd7921
Author(s):  
Yoon Seok Kim ◽  
Sojung Kang ◽  
Jae-Pil So ◽  
Jong Chan Kim ◽  
Kangwon Kim ◽  
...  
Keyword(s):  
Transition Metal ◽  
Quantum Wells ◽  
Building Block ◽  
Transition Metal Dichalcogenides ◽  
Atomic Layer ◽  
Band Alignment ◽  
Type I ◽  
Bandgap Engineering ◽  
Strong Light ◽  
Metal Dichalcogenides

Quantum wells (QWs), enabling effective exciton confinement and strong light-matter interaction, form an essential building block for quantum optoelectronics. For two-dimensional (2D) semiconductors, however, constructing the QWs is still challenging because suitable materials and fabrication techniques are lacking for bandgap engineering and indirect bandgap transitions occur at the multilayer. Here, we demonstrate an unexplored approach to fabricate atomic–layer–confined multiple QWs (MQWs) via monolithic bandgap engineering of transition metal dichalcogenides and van der Waals stacking. The WOX/WSe2 hetero-bilayer formed by monolithic oxidation of the WSe2 bilayer exhibited the type I band alignment, facilitating as a building block for MQWs. A superlinear enhancement of photoluminescence with increasing the number of QWs was achieved. Furthermore, quantum-confined radiative recombination in MQWs was verified by a large exciton binding energy of 193 meV and a short exciton lifetime of 170 ps. This work paves the way toward monolithic integration of band-engineered heterostructures for 2D quantum optoelectronics.

Valence-Mending Passivation of Si(100) Surface: Principle, Practice and Application

2015 ◽  
Vol 242 ◽  
pp. 51-60 ◽  
Author(s):  
Meng Tao
Keyword(s):  
Transition Metal ◽  
Schottky Barrier Height ◽  
New Records ◽  
Transition Metal Dichalcogenides ◽  
Surface States ◽  
Atomic Layer ◽  
Schottky Barriers ◽  
Photovoltaic Devices ◽  
Dangling Bonds ◽  
Metal Dichalcogenides

Surface states have hindered and degraded many semiconductor devices since the Bardeen era. Surface states originate from dangling bonds on the surface. This paper discusses a generic solution to surface states, i.e. valence-mending passivation. For the Si (100) surface, a single atomic layer of valence-mending sulfur, selenium or tellurium can terminate ~99% of the dangling bonds, while group VII fluorine or chlorine can terminate the remaining 1%. Valence-mending passivation of Si (100) has been demonstrated using CVD, MBE and solution passivation. The keys to valence-mending passivation include an atomically-clean Si (100) surface for passivation and precisely one monolayer of valence-mending atoms on the surface. The passivated surface exhibits unprecedented properties. Electronically the Schottky barrier height between various metals and valence-mended Si (100) now follows more closely the Mott-Schottky theory. With metals of extreme workfunctions, new records for low and high Schottky barriers are created on Si (100). The highest barrier so far is 1.14 eV, i.e. a larger-than-bandgap barrier, and the lowest barrier is below 0.08 eV and potentially negative. Chemically silicidation between metal and valence-mended Si (100) is suppressed up to 500 °C, and the thermally-stable record Schottky barriers enable their applications in nanoelectronic, optoelectronic and photovoltaic devices. Another application is transition metal dichalcogenides. Valence-mended Si (100) is an ideal starting surface for growth of dichalcogenides, as it provides only van der Waals bonding to the dichalcogenide.

Type-I Transition Metal Dichalcogenides Lateral Homojunctions: Layer Thickness and External Electric Field Effects

Small ◽  
2018 ◽  
Vol 14 (21) ◽  
pp. 1800365 ◽  
Author(s):  
Congxin Xia ◽  
Wenqi Xiong ◽  
Juan Du ◽  
Tianxing Wang ◽  
Yuting Peng ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electric Field ◽  
Layer Thickness ◽  
External Electric Field ◽  
Transition Metal Dichalcogenides ◽  
Type I ◽  
Electric Field Effects ◽  
Field Effects ◽  
Metal Dichalcogenides

Highly-efficient heterojunction solar cells based on two-dimensional tellurene and transition metal dichalcogenides

2019 ◽  
Vol 7 (13) ◽  
pp. 7430-7436 ◽  
Author(s):  
Kai Wu ◽  
Huanhuan Ma ◽  
Yunzhi Gao ◽  
Wei Hu ◽  
Jinlong Yang
Keyword(s):  
Solar Cells ◽  
Transition Metal ◽  
Charge Separation ◽  
Transition Metal Dichalcogenides ◽  
Band Alignment ◽  
Type Ii ◽  
Two Dimensional ◽  
Heterojunction Solar Cells ◽  
Highly Efficient ◽  
Metal Dichalcogenides

Tellurene and TMDs show desirable type II band alignment for constructing highly-efficient heterojunction solar cells with strong charge separation and enhanced sunlight absorption.

scholarly journals Composition-induced type I and direct bandgap transition metal dichalcogenides alloy vertical heterojunctions

Nanoscale ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 201-209 ◽  
Author(s):  
Songsong Zhou ◽  
Jinliang Ning ◽  
Jianwei Sun ◽  
David J. Srolovitz
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Type I ◽  
Transition Metal Dichalcogenide ◽  
Direct Bandgap ◽  
Metal Dichalcogenides

Using alloying and/or twisting between layers to achieve the type I direct bandgaps vertical heterojunction in transition metal dichalcogenide family of MX2 (M = {Mo, W}, X = {S, Se}).

scholarly journals Experimental observation of topological Z2 exciton-polaritons in transition metal dichalcogenide monolayers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mengyao Li ◽  
Ivan Sinev ◽  
Fedor Benimetskiy ◽  
Tatyana Ivanova ◽  
Ekaterina Khestanova ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Strong Light ◽  
Strongly Coupled ◽  
Exciton Polaritons ◽  
Valley Polarization ◽  
Topological States ◽  
Metal Dichalcogenides ◽  
Quantum Science

AbstractThe rise of quantum science and technologies motivates photonics research to seek new platforms with strong light-matter interactions to facilitate quantum behaviors at moderate light intensities. Topological polaritons (TPs) offer an ideal platform in this context, with unique properties stemming from resilient topological states of light strongly coupled with matter. Here we explore polaritonic metasurfaces based on 2D transition metal dichalcogenides (TMDs) as a promising platform for topological polaritonics. We show that the strong coupling between topological photonic modes of the metasurface and excitons in TMDs yields a topological polaritonic Z2 phase. We experimentally confirm the emergence of one-way spin-polarized edge TPs in metasurfaces integrating MoSe2 and WSe2. Combined with the valley polarization in TMD monolayers, the proposed system enables an approach to engage the photonic angular momentum and valley and spin of excitons, offering a promising platform for photonic/solid-state interfaces for valleytronics and spintronics.

scholarly journals Band alignment of two-dimensional transition metal dichalcogenides: Application in tunnel field effect transistors

2013 ◽  
Vol 103 (5) ◽  
pp. 053513 ◽  
Author(s):  
Cheng Gong ◽  
Hengji Zhang ◽  
Weihua Wang ◽  
Luigi Colombo ◽  
Robert M. Wallace ◽  
...  
Keyword(s):  
Transition Metal ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Transition Metal Dichalcogenides ◽  
Band Alignment ◽  
Two Dimensional ◽  
Metal Dichalcogenides

MoS2-capped CuxS nanocrystals: a new heterostructured geometry of transition metal dichalcogenides for broadband optoelectronics

2019 ◽  
Vol 6 (3) ◽  
pp. 587-594 ◽  
Author(s):  
Yuan Li ◽  
Akshay A. Murthy ◽  
Jennifer G. DiStefano ◽  
Hee Joon Jung ◽  
Shiqiang Hao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Performance Improvement ◽  
Transition Metal Dichalcogenides ◽  
Band Alignment ◽  
Next Generation ◽  
Semiconductor Electronics ◽  
Metal Dichalcogenides ◽  
And Performance

Heterostructuring of different transition metal dichalcogenides (TMDs) leads to interesting band alignment and performance improvement, and thus enables new routes for the development of materials for next-generation semiconductor electronics.

Sign in / Sign up

Export Citation Format

Share Document