scholarly journals Charge-Transfer Induced by the Oxygen Vacancy Defects in the Ag/MoO3 Composite System

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1292
Author(s):  
Qi Chu ◽  
Jingmeng Li ◽  
Sila Jin ◽  
Shuang Guo ◽  
Eungyeong Park ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Oxygen Vacancy ◽  
Composite System ◽  
Wide Band ◽  
Utilization Rate ◽  
Wide Band Gap ◽  
Interesting Phenomenon ◽  
Vacancy Defects ◽  
Characterization Methods ◽  
Surface Enhanced Raman

In this paper, an Ag/MoO3 composite system was cosputtered by Ar plasma bombardment on a polystyrene (PS) colloidal microsphere array. The MoO3 formed by this method contained abundant oxygen vacancy defects, which provided a channel for charge transfer in the system and compensated for the wide band gap of MoO3. Various characterization methods strongly demonstrated the existence of oxygen vacancy defects and detected the properties of oxygen vacancies. 4-Aminothiophenol (p-aminothiophenol, PATP) was used as a candidate surface-enhanced Raman scattering (SERS) probe molecule to evaluate the contribution of the oxygen vacancy defects in the Ag/MoO3 composite system. Interestingly, oxygen vacancy defects are a kind of charge channel, and their powerful effect is fully reflected in their SERS spectra. Increasing the number of charge channels and increasing the utilization rate of the channels caused the frequency of SERS characteristic peaks to shift. This interesting phenomenon opens up a new horizon for the study of SERS in oxygen-containing semiconductors and provides a powerful reference for the study of PATP.

scholarly journals Development of β-Ga2O3 layers growth on sapphire substrates employing modeling of precursors ratio in halide vapor phase epitaxy reactor

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Galia Pozina ◽  
Chih-Wei Hsu ◽  
Natalia Abrikossova ◽  
Mikhail A. Kaliteevski ◽  
Carl Hemmingsson
Keyword(s):  
Band Gap ◽  
Vapor Phase ◽  
Wide Band ◽  
Band Gap Energy ◽  
Vapor Phase Epitaxy ◽  
Structural Quality ◽  
Wide Band Gap ◽  
Vacancy Defects ◽  
Sapphire Substrates ◽  
Efficient Power

AbstractGallium oxide is a promising semiconductor with great potential for efficient power electronics due to its ultra-wide band gap and high breakdown electric field. Optimization of halide vapor phase epitaxy growth of heteroepitaxial $$\upbeta$$ β -Ga2O3 layers is demonstrated using a simulation model to predict the distribution of the ratio of gallium to oxygen precursors inside the reactor chamber. The best structural quality is obtained for layers grown at 825–850 °C and with a III/VI precursor ratio of 0.2. Although the structural and optical properties are similar, the surface morphology is more deteriorated for the $$\upbeta$$ β -Ga2O3 layers grown on 5 degree off-axis sapphire substrates compared to on-axis samples even for optimized process parameters. Cathodoluminescence with a peak at 3.3 eV is typical for unintentionally doped n-type $$\upbeta$$ β -Ga2O3 and shows the appearance of additional emissions in blue and green region at ~ 3.0, ~ 2.8, ~ 2.6 and ~ 2.4 eV, especially when the growth temperatures is lowered to 800–825 °C. Estimation of the band gap energy to ~ 4.65 eV from absorption indicates a high density of vacancy defects.

scholarly journals Ab-Initio Calculations of Oxygen Vacancy in Ga2O3 Crystals

2021 ◽  
Vol 58 (2) ◽  
pp. 3-10
Author(s):  
A. Usseinov ◽  
Zh. Koishybayeva ◽  
A. Platonenko ◽  
A. Akilbekov ◽  
J. Purans ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Gallium Oxide ◽  
Formation Energy ◽  
Oxygen Vacancies ◽  
Wide Band ◽  
Electronic Charge ◽  
Charge Redistribution ◽  
Wide Band Gap ◽  
Exchange Correlation ◽  
Deep Donor

Abstract Gallium oxide β-Ga2O3 is an important wide-band gap semiconductor. In this study, we have calculated the formation energy and transition levels of oxygen vacancies in β-Ga2O3 crystal using the B3LYP hybrid exchange-correlation functional within the LCAO-DFT approach. The obtained electronic charge redistribution in perfect Ga2O3 shows notable covalency of the Ga-O bonds. The formation of the neutral oxygen vacancy in β-Ga2O3 leads to the presence of deep donor defects with quite low concentration. This is a clear reason why oxygen vacancies can be hardly responsible for n-type conductivity in β-Ga2O3.

Novel N-Black In2O3-x/InVO4 heterojunction for efficient photocatalytic fixation: Synergistic effect of exposed (321) facet and oxygen vacancy

2021 ◽  
Author(s):  
Jin Ye ◽  
Jiating Xu ◽  
Chunsheng Li ◽  
Di Tian ◽  
Xiaohan Zhao ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Synergistic Effect ◽  
Band Gap ◽  
Recombination Rate ◽  
Wide Band ◽  
Great Promise ◽  
Wide Band Gap ◽  
High Recombination Rate ◽  
Energy Shortage

Utilizing semiconductors to catalyze N2 into NH3 has brought great promise in alleviating the issue of energy shortage. However, the wide band gap and high recombination rate of photogenerated (e-/h+)...

Application of Wide Band Gap Semiconductors to Increase Photocurrent in a Protein Based Photovoltaic Device

2012 ◽  
Vol 1414 ◽  
Author(s):  
Arash Takshi ◽  
Houman Yaghoubi ◽  
Daniel Jun ◽  
Rafael Saer ◽  
Ali Mahmoudzadeh ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Indium Tin Oxide ◽  
Wide Band ◽  
Photocurrent Density ◽  
Wide Bandgap ◽  
Semiconducting Materials ◽  
Wide Band Gap ◽  
Electron Hole ◽  
New Approach ◽  
Wide Band Gap Semiconductors

ABSTRACTReaction centers (RCs) from natural photosynthetic cells are photoactive proteins, which generate electron-hole pairs in presence of light. In a new approach presented in this work, a solution of suspended RCs with mediators has been applied as the electrolyte to build electrochemical based photovoltaic (PV) devices. In this approach, the mediators transfer charges from the RCs to the electrodes (indirect charge transfer). Various metallic and wide bandgap semiconducting materials, including Carbon, Au, Indium Tin Oxide (ITO), SnO2, WO3, have been tested as the electrodes. Among all WO3, which is a semiconductor, have shown the largest photocurrent density with an amount of ∼5.1 μA/cm2. The results show that the material of the electrode can affect the rates of the reactions in the cell. Choosing an appropriate material for the electrode, the charge transfer from the mediators to the electrode would be rectified to achieve a large photocurrent.

TEM and cathodoluminescence of precipitates in II-VI semiconductors

1988 ◽  
Vol 46 ◽  
pp. 488-489
Author(s):  
Joanna L. Batstone
Keyword(s):  
Crystal Growth ◽  
Band Gap ◽  
Local Strain ◽  
Wide Band ◽  
Optoelectronic Device ◽  
Wide Band Gap ◽  
Bulk Crystal Growth ◽  
Transmission Electron ◽  
Device Applications ◽  
Stoichiometry Control

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.

Electron microscopic characterization of diamond thin films and substrates for diamond heteroepitaxial growth

1989 ◽  
Vol 47 ◽  
pp. 592-593
Author(s):  
J.B. Posthill ◽  
R.P. Burns ◽  
R.A. Rudder ◽  
Y.H. Lee ◽  
R.J. Markunas ◽  
...  
Keyword(s):  
Thin Films ◽  
Wide Band ◽  
Deposition Process ◽  
Heteroepitaxial Growth ◽  
Electron Microscopic ◽  
Wide Band Gap ◽  
Lattice Matching ◽  
Different Types ◽  
Diamond Thin Films

Because of diamond’s wide band gap, high thermal conductivity, high breakdown voltage and high radiation resistance, there is a growing interest in developing diamond-based devices for several new and demanding electronic applications. In developing this technology, there are several new challenges to be overcome. Much of our effort has been directed at developing a diamond deposition process that will permit controlled, epitaxial growth. Also, because of cost and size considerations, it is mandatory that a non-native substrate be developed for heteroepitaxial nucleation and growth of diamond thin films. To this end, we are currently investigating the use of Ni single crystals on which different types of epitaxial metals are grown by molecular beam epitaxy (MBE) for lattice matching to diamond as well as surface chemistry modification. This contribution reports briefly on our microscopic observations that are integral to these endeavors.

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