scholarly journals A Theoretical Framework for Microscopic Surface and Interface Dipoles, Work Functions, and Valence Band Alignments in 2D and 3D Halide Perovskite Heterostructures

2021 ◽  
pp. 349-357
Author(s):  
Boubacar Traoré ◽  
Pooja Basera ◽  
Alexandra J. Ramadan ◽  
Henry J. Snaith ◽  
Claudine Katan ◽  
...  
Keyword(s):  
Valence Band ◽  
Theoretical Framework ◽  
Surface And Interface ◽  
Band Alignments ◽  
Work Functions ◽  
Halide Perovskite ◽  
2D And 3D ◽  
Microscopic Surface

scholarly journals Investigation of Band Alignment for Hybrid 2D-MoS2/3D-β-Ga2O3 Heterojunctions with Nitridation

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Ya-Wei Huan ◽  
Ke Xu ◽  
Wen-Jun Liu ◽  
Hao Zhang ◽  
Dmitriy Anatolyevich Golosov ◽  
...  
Keyword(s):  
Valence Band ◽  
Transition Metal Dichalcogenides ◽  
Three Dimensional ◽  
Optoelectronic Devices ◽  
Band Alignment ◽  
Band Offsets ◽  
Group Iii ◽  
Nanoelectronic Devices ◽  
Metal Dichalcogenides ◽  
Band Alignments

AbstractHybrid heterojunctions based on two-dimensional (2D) and conventional three-dimensional (3D) materials provide a promising way toward nanoelectronic devices with engineered features. In this work, we investigated the band alignment of a mixed-dimensional heterojunction composed of transferred MoS2 on β-Ga2O3($$ 2- $$2-01) with and without nitridation. The conduction and valence band offsets for unnitrided 2D-MoS2/3D-β-Ga2O3 heterojunction were determined to be respectively 0.43 ± 0.1 and 2.87 ± 0.1 eV. For the nitrided heterojunction, the conduction and valence band offsets were deduced to 0.68 ± 0.1 and 2.62 ± 0.1 eV, respectively. The modified band alignment could result from the dipole formed by charge transfer across the heterojunction interface. The effect of nitridation on the band alignments between group III oxides and transition metal dichalcogenides will supply feasible technical routes for designing their heterojunction-based electronic and optoelectronic devices.

NOVEL MEASUREMENT OF THE BAND DISCONTINUITIES IN (Al,Ga)As HETEROJUNCTIONS

1985 ◽  
Vol 56 ◽  
Author(s):  
B. A. WILSON ◽  
P. DAWSON ◽  
C. W. TU ◽  
R. C. MILLER
Keyword(s):  
Valence Band ◽  
Binding Energies ◽  
Band Alignment ◽  
Material System ◽  
Valence Band Offset ◽  
Quantum Well Structures ◽  
Accurate Knowledge ◽  
Novel Method ◽  
Band Alignments ◽  
Valence Band Discontinuity

AbstractA novel method has been used to obtain a direct and accurate measure of the valence-band discontinuity AlyGa1−yAs/AlAs heterojunctions in quantum-well structures. The technique takes advantage of the crossover occurring at a critical Al concentration above which the indirect X minimum in the AlAs becomes the lowest-energy conduction band in the system. Within these “staggered” band alignment structures, photoexcited electrons and holes are spatially separated, and recombination occurs across the interface. The resulting emission fixes the valence-band offset to within 1% without accurate knowledge of other system parameters, such as effective masses and exciton or dopant binding energies. These measurements represent the first direct optical confirmation of staggered band alignments in this technologically important material system.

Staggered band alignments in AlGaAs heterojunctions and the determination of valence‐band offsets

1986 ◽  
Vol 48 (8) ◽  
pp. 541-543 ◽  
Author(s):  
P. Dawson ◽  
B. A. Wilson ◽  
C. W. Tu ◽  
R. C. Miller
Keyword(s):  
Valence Band ◽  
Band Offsets ◽  
Band Alignments

scholarly journals Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu3BiS3 for Photovoltaics

2019 ◽  
Vol 11 (30) ◽  
pp. 27033-27047 ◽  
Author(s):  
Thomas J. Whittles ◽  
Tim D. Veal ◽  
Christopher N. Savory ◽  
Peter J. Yates ◽  
Philip A. E. Murgatroyd ◽  
...  
Keyword(s):  
Band Gap ◽  
Valence Band ◽  
Band Alignments

Stress Effects in p-Type AlGaN/GaN Heterostructures

2001 ◽  
Vol 680 ◽  
Author(s):  
Agustinus Sutandi ◽  
P. Paul Ruden ◽  
Kevin F. Brennan
Keyword(s):  
Valence Band ◽  
Interfacial Polarization ◽  
Defect States ◽  
Surface And Interface ◽  
Linear Elastic ◽  
Stress Effects ◽  
Interface Defect ◽  
Bulk Surface ◽  
Linear Elastic Theory ◽  
P Type

ABSTRACTThe physics of bulk wurtzite-structure III-nitride materials and of III-nitride heterostructures includes many phenomena that can be modulated by the application of stress. In particular, p- type material is expected to display a rich variety of piezo-resistive and piezo-optic effects that originate from the stress-induced modulation of lattice polarization charges, of valence band energies, and of bulk, surface, and interface defect states in the band gap. Here we focus on the expected effects of in-plane uniaxial on p-channel AlGaN/GaN heterostructures grown along the hexagonal axis on sapphire substrates. The valence band structure in the channel region is calculated self-consistently in the framework of a six-band Rashba-Sheka-Pikus (RSP) Hamiltonian. Stress-effects are included (in linear elastic theory) through deformation potentials and through the modulation of interfacial polarization charges associated with the piezoelectric nature of the constituent materials.

scholarly journals Al Composition Dependence of Band Offsets for SiO2 on α-(AlxGa1-x)2O3

2021 ◽  
Author(s):  
Xinyi Xia ◽  
Chaker Fares ◽  
Fan Ren ◽  
Anna Hassa ◽  
Holger von Wenckstern ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Composition Dependence ◽  
Atomic Layer ◽  
Wide Bandgap ◽  
Band Alignment ◽  
Band Offsets ◽  
Layer Deposition ◽  
Semiconductor System ◽  
Band Alignments

Abstract Valence band offsets were measured by X Ray Photoelectron Spectroscopy for SiO2 deposited by Atomic Layer Deposition on α-(AlxGa1-x)2O3 alloys with x= 0.26-0.74 grown with a continuous composition spread to enable investigations of the band alignment as a function of the alloy composition. From measurement of the core levels in the alloys, the bandgaps were determined to range from 5.8 eV (x=0.26) to 7eV (x=0.74). The valence band offsets were -1.2 eV for x=0.26, -0.2 eV for x=0.42, 0.2 eV for x=0.58 and 0.4 eV for x=0.74. Given the bandgap of the SiO2 was 8.7 eV, this led to conduction band offsets of 4.1 eV (x=0.26) to 1.3 eV (x=0.74). The band alignments were nested for x>0.5 , but at lower Al contents the conductions band offsets were negative, with a staggered band alignment. This shows the challenge of finding appropriate dielectrics for this ultra-wide bandgap semiconductor system.

Band alignments and heterostructures of monolayer transition metal trichalcogenides MX3 (M = Zr, Hf; X = S, Se) and dichalcogenides MX2 (M = Tc, Re; X=S, Se) for solar applications

Nanoscale ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 3547-3555 ◽  
Author(s):  
Qiyi Zhao ◽  
Yaohui Guo ◽  
Yixuan Zhou ◽  
Zehan Yao ◽  
Zhaoyu Ren ◽  
...  
Keyword(s):  
Transition Metal ◽  
Band Gaps ◽  
Band Alignments ◽  
Work Functions ◽  
Solar Applications

The band gaps and work functions of monolayer IVB-VIA 2D TMTs MX3 and VIIB-VIA 2D TMDs MX2 are calculated and their band alignments and the relevant physical origins of the band alignments are investigated.

Electronic implications of organic nitrogen lone pairs in lead iodide perovskites

2018 ◽  
Vol 6 (17) ◽  
pp. 4765-4768 ◽  
Author(s):  
Thomas W. Kasel ◽  
Christopher H. Hendon
Keyword(s):  
Valence Band ◽  
Organic Nitrogen ◽  
Lead Iodide ◽  
Lone Pairs ◽  
Halide Perovskite

Nitrogen lone pairs unfavorably contribute to the valence band in hybrid halide perovskite architectures.

A Unified Theoretical Framework to Model Bulk, Surface and Interfacial Thermodynamic Properties of Immiscible Liquid Alloys

2013 ◽  
Vol 752 ◽  
pp. 10-19 ◽  
Author(s):  
Ádám Végh ◽  
Csaba Mekler ◽  
György Kaptay
Keyword(s):  
Phase Transition ◽  
Surface Tension ◽  
Thermodynamic Properties ◽  
Theoretical Framework ◽  
Immiscible Liquid ◽  
Liquid Alloys ◽  
Surface Phase ◽  
Surface And Interface ◽  
Bulk Surface ◽  
Exponential Equations

Bulk, surface and interface thermodynamics of immiscible liquid alloys are considered within a unified theoretical framework. For bulk thermodynamic functions the exponential and the combined linear-exponential equations are discussed, obeying the 4th law of thermodynamics. Surface phase transition is discussed in details. For surface and interface thermodynamics the monolayer Butler equation is compared to the multilayer model. During further assessment of bulk thermodynamic data of immiscible liquid alloys their experimentally measured surface tension and interfacial energy should be also taken into account, coupled with the models presented here.

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