Ultra-small (r<2 nm), stable (>1 year) copper oxide quantum dots with wide band gap

Electronic properties of exciton in Mg based ZnS, ZnSe and ZnTe wide band gap semiconductor cylindrical quantum dots are investigated taking into consideration of geometrical confinement effect. The confinement potentials for various concentrations of Mg alloy content in Zn1–xMgxS/MgS, Zn1–xMgxSe/MgSe and Zn1–xMgxTe/MgTe quantum dots are studied and the constant barrier height is maintained for the Mg content in all the three heterostructures (Zn0.9Mg0.1S/MgS, Zn0.25Mg0.75Se/MgSe and Zn0.09Mg0.91Te/MgTe) to obtain the exciton binding energies and the optical transition energies. The results show that the band gap increases nonlinearly with the increase of composition of Mg alloy content in the taken materials due to the positive band gap bowing parameters and the exciton binding energies in Zn0.9Mg0.1S/MgS quantum dot are found to be more than the other two dots taken for studies. Our results will be helpful for some potential applications in full colour display devices and optical data storage devices.

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Improving the photoresponsivity and reducing the persistent photocurrent effect of visible-light ZnO/quantum-dot phototransistors via a TiO2 layer

Journal of Materials Chemistry C ◽

10.1039/d0tc03353g ◽

2020 ◽

Vol 8 (46) ◽

pp. 16384-16391

Author(s):

Byung Jun Kim ◽

Sungho Park ◽

Tae Yeon Kim ◽

Eui Young Jung ◽

Jong-Am Hong ◽

...

Keyword(s):

Quantum Dots ◽

Zinc Oxide ◽

Quantum Dot ◽

Visible Light ◽

Band Gap ◽

Wide Band ◽

Colloidal Quantum Dots ◽

Tio2 Layer ◽

Wide Band Gap

Conventional visible-light phototransistors based on the heterostructure of wide band gap zinc oxide (ZnO) and colloidal quantum-dots (CdSe/ZnS QDs) have been studied.

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Formation and characteristics of wide band gap II-VI semiconductor quantum dots

Proceedings of the Sixth Chinese Optoelectronics Symposium (IEEE Cat. No.03EX701) ◽

10.1109/cos.2003.1278156 ◽

2004 ◽

Author(s):

X.W. Fan ◽

C.X. Shan ◽

Y. Yang ◽

J.Y. Zhang ◽

Y.C. Liu ◽

...

Keyword(s):

Quantum Dots ◽

Band Gap ◽

Wide Band ◽

Semiconductor Quantum Dots ◽

Wide Band Gap

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Wide Band Gap Quantum Dots Sensitized α-Fe2O3 Thin Film for Solar Generation of Hydrogen

MRS Proceedings ◽

10.1557/opl.2015.279 ◽

2015 ◽

Vol 1738 ◽

Author(s):

Ashi Ikram ◽

Sonal Sahai ◽

Snigdha Rai ◽

Sahab Dass ◽

Rohit Shrivastav ◽

...

Keyword(s):

Quantum Dots ◽

Band Gap ◽

Recombination Rate ◽

Wide Band ◽

Photocurrent Density ◽

Flat Band ◽

Present System ◽

Wide Band Gap ◽

Carrier Recombination ◽

Zno Qds

ABSTRACTPresent study investigates the system of small and large band gap materials for their use in Photoelectrochemical splitting of water. Electrodeposited Zr doped hematite (α-Fe2O3) films were subjected to ZnO quantum dots sensitization for 24, 48, and 72 hours which later on characterized for optical, structural, morphological and photoelectrochemical properties. These sensitized films, when used as photoelectrode in PEC cell, showed a significant increase in the photocurrent density as compared to unsensitized films. This may be attributed to reduction in carrier recombination rate along with photocatalytic effect of ZnO. The enhanced photo response has also been supported by increased negative value of flat band potential from -0.29V/SCE for unsensitized film to -0.8V/SCE for ZnO QDs sensitized hematite film, as examined by Mott-Schottky curve. In the present system, small band gap hematite has been chosen as a main solar energy absorber, while wide band gap ZnO QDs decorated over it, as an efficient electron transport across the interface by reducing charge carrier recombination rate.

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On the Burste In-Moss Shift in Quantum Confined Wide-Band Gap Semiconductors

MRS Proceedings ◽

10.1557/proc-242-373 ◽

1992 ◽

Vol 242 ◽

Cited By ~ 2

Author(s):

Kamakhya P. Ghatak ◽

Badal De

Keyword(s):

Quantum Dots ◽

Theoretical Analysis ◽

Quantum Wells ◽

Band Gap ◽

Electron Concentration ◽

Wide Band ◽

Experimental Results ◽

Wide Band Gap ◽

Wide Band Gap Semiconductors ◽

Wide Gap

ABSTRACTWe study the Burstein-Moss shift (BMS) in quantum wiies and quantum dots of wide-gap semiconductors, taking Ge as an example, it is found that the BMS increases with increasing electron concentration in a ladder like manner. The numerical values of the BMS is greatest in quantum dots and least in quantum wells. The theoretical analysis is in agreement with the experimental results as given elsewhere.

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TEM and cathodoluminescence of precipitates in II-VI semiconductors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104509 ◽

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.

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