Important roles of native-oxides on the electronic band offsets at Ge-oxide/Ge(0 0 1) heterojunction in ambient environment

2020 ◽  
Vol 530 ◽  
pp. 147256
Author(s):  
Bin Leong Ong ◽  
Sheau Wei Ong ◽  
Andrivo Rusydi ◽  
Eng Soon Tok
Keyword(s):  
Electronic Band ◽  
Band Offsets ◽  
Ambient Environment ◽  
Native Oxides

Electronic band-offsets across Cu2O/BaZrO3 heterojunction and its stable photo-electro-chemical response: First-principles theoretical analysis and experimental optimization

2017 ◽  
Vol 113 ◽  
pp. 503-511 ◽  
Author(s):  
Dipika Sharma ◽  
Rishibrind Kumar Upadhyay ◽  
Biswarup Satpati ◽  
Vibha R. Satsangi ◽  
Rohit Shrivastav ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
First Principles ◽  
Electronic Band ◽  
Band Offsets ◽  
Experimental Optimization ◽  
Chemical Response

Photocurrent Response of Composite Perovskite Oxide Thin Films With Specific Semiconducting and Ferroelectric Properties

2013 ◽  
Author(s):  
Jay Shieh ◽  
Szu-Wei Chen ◽  
Chia-Yu Fang
Keyword(s):  
Thin Film ◽  
Photocurrent Density ◽  
Perovskite Oxide ◽  
Material Interface ◽  
Electronic Band ◽  
Band Bending ◽  
Band Offsets ◽  
Thin Film Composites ◽  
Layered Thin Film ◽  
Film Composites

The goal of this study is to investigate photocatalytic semiconductor systems which are layered thin film composites built from perovskite oxide materials with characteristics such as small and large band gaps and/or ferroelectricity. In order to improve the efficiency of photocatalysis, semiconductor heterojunctions within the developed composites have been designed to possess electronic band offsets favoring the separation of photo-induced electron and hole (e−/h+) pairs. Furthermore, the remanent polarization of the ferroelectric component within the composites has been utilized to induce favorable band bending at the material interface, lowering the potential barrier for electron transfer. The band offsets and ferroelectric polarization could be considered as built-in electric fields; how they interact with photo-induced e−/h+ would greatly affect the photocatalytic properties of the composites. In this study, various perovskite oxide thin film materials — large band gap strontium titanate (SrTiO3), small band gap silver niobate (AgNbO3) and ferroelectric lead lanthanum titanate (PLT) — were combined to form layered thin film composites. The composites were then adopted as photoanodes in a photoelectrochemical cell and detailed characterization of their photocurrent response was carried out under different light irradiation and ferroelectric polarization conditions. Electronic band offsets at the material interface (i.e., heterojunction) were determined by ultraviolet-visible spectrophotometry and ultraviolet photoelectron spectroscopy. Electric field poling of the ferroelectric component was achieved by non-contact corona charging. Our results have shown that the band offsets at the SrTiO3-AgNbO3 heterojunction were about 1.0 eV in conduction band edge and 0.4 eV in valence band edge, promoting the rapid separation of photo-induced charge carriers; i.e., the flow of e− from SrTiO3 to AgNbO3 and the flow of h+ from AgNbO3 to SrTiO3. It was found that ferroelectric PLT could be used as a seeding layer for the low-temperature (500 °C) growth of SrTiO3/AgNbO3 thin film composites on ITO/glass substrates, forming a layered structure of SrTiO3/AgNbO3/PLT/ITO. In addition, the photocurrent density of the composites could be increased by depositing gold nanoparticles at the PLT-ITO interface. When the polarization of the PLT layer was poled toward the AgNbO3 layer, the potential barrier associated with the flow of e− to the ITO electrode was reduced by favorable band bending created at the AgNbO3-PLT interface. This resulted in a significant increase in photocurrent density.

scholarly journals Band Offsets at Strained-Layer Interfaces

1987 ◽  
Vol 102 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Electronic Band ◽  
Band Offsets ◽  
Strained Layer ◽  
Device Applications ◽  
Absolute Energy ◽  
Local Density Functional ◽  
Lattice Matched

ABSTRACTStrained-layer heterojunctions and superlattices have recently shown tremendous potential for device applications because of their flexibility for tailoring the electronic band structure. We present a theoretical model to predict the band offsets at both lattice-matched and pseudomorphic strained-layer interfaces. The theory is based on the local-density- functional pseudopotential formalism, and the “model solid approach” of Van de Walle and Martin. The results can be most simply expressed in terms of an “absolute” energy level for each semiconductor, and deformation potentials that describe the effects of strain on the electronic bands. The model predicts reliable values for the experimentally observed lineups in Si/Ge, GaAs/InAs, and ZnSe/ZnS systems, and can be used to ex-plore which combinations of materials and configurations of the strains will lead to the desired electronic properties.

Optical spectroscopic determination of the electronic band structure of bulk AlGaInP and GaInP-AlGaInP heterojunction band offsets

1997 ◽  
Author(s):  
David J. Mowbray ◽  
Olgierd P. Kowalski ◽  
John W. Cockburn ◽  
Maurice S. Skolnick ◽  
Mark Hopkinson ◽  
...  
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Spectroscopic Determination ◽  
Electronic Band ◽  
Band Offsets

The electronic band structure of silicon

Physica ◽  
1954 ◽  
Vol 3 (7-12) ◽  
pp. 967-970
Author(s):  
D JENKINS
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band

THE ELECTRONIC BAND STRUCTURE OF V3Ga AND V3Si

1972 ◽  
Vol 33 (C3) ◽  
pp. C3-223-C3-233 ◽  
Author(s):  
I. B. GOLDBERG ◽  
M. WEGER
Keyword(s):  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band

Ab initio calculation on the Optical Properties of AA- Stacked two dimensional Graphene, Silicene, Germanene, and Stanene

2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Complex Refractive Index ◽  
Single Layer ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Wide Range ◽  
Optical Region

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.

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