Size Dependent Electroluminescence from CdSe Nanocrystallites (Quantum Dots)

1994 ◽  
Vol 358 ◽  
Author(s):  
B.O. Dabbousi ◽  
O. Onitsuka ◽  
M.F. Rubner ◽  
M.G. Bawendi
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Room Temperature ◽  
Variable Temperature ◽  
Cryogenic Temperatures ◽  
Photoluminescence Spectra ◽  
Size Dependent

ABSTRACTWe obtain spectrally narrow (FWHM < 40 nm) electroluminescence from nearly monodisperse CdSe nanocrystallites (quantum dots) incorporated into thin films of polyvinyl carbazole (PVK) and an oxadiazole derivative (PBD) sandwiched between aluminum and ITO electrodes. The electroluminescence and photoluminescence spectra are nearly identical at room temperature and are tunable from ∼530 nm to ∼650 nm by varying the size of the dots. Voltage studies at 77K indicate that while only the dots electroluminesce at the lower voltages, both the dots and the PVK matrix electroluminesce at higher applied voltages. Variable temperature studies indicate that the electroluminescence efficiency increases substantially as the films are cooled down to cryogenic temperatures.

scholarly journals Optical and Structural Properties of CdS Quantum Dots Synthesized Using (MW-CBD) Technique

2020 ◽  
pp. 44-52
Author(s):  
Ahmed Ahmed S. Abed ◽  
Sattar J. Kasim ◽  
Abbas F. Abbas
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Room Temperature ◽  
Energy Gap ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
High Adhesion ◽  
Uv Visible

In the present study, the microwave heating method was used to prepare cadmium sulfide quantum dots CdSQDs films. CdS nanoparticles size average obtained as (7nm). The morphology, structure and composition of prepared CdSQDs were examined using (FE-SEM), (XRD) and (EDX). Optical properties of CdSQDs thin films formed and deposited onto glass substrates have been studied at room temperature using UV/ Visible spectrophotometer within the wavelength of (300-800nm), and Photoluminescence (PL) spectrum. The optical energy gap (Eg) which estimated using Tauc relation was equal (2.6eV). Prepared CdS nanoparticles thin films are free from cracks, pinholes and have high adhesion to substrate.

scholarly journals Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension

2015 ◽  
Vol 60 (1) ◽  
pp. 365-370 ◽  
Author(s):  
M. Granata ◽  
L. Balzarini ◽  
J. Degallaix ◽  
V. Dolique ◽  
R. Flaminio ◽  
...  
Keyword(s):  
Thin Films ◽  
Internal Friction ◽  
Silicon Wafer ◽  
Room Temperature ◽  
Suspension System ◽  
Cryogenic Temperatures ◽  
Resonant Frequencies ◽  
High Q ◽  
Key Features ◽  
Q Factors

Abstract In order to study the internal friction of thin films a nodal suspension system called GeNS (Gentle Nodal Suspension) has been developed. The key features of this system are: i) the possibility to use substrates easily available like silicon wafers; ii) extremely low excess losses coming from the suspension system which allows to measure Q factors in excess of 2×108 on 3” diameter wafers; iii) reproducibility of measurements within few percent on mechanical losses and 0.01% on resonant frequencies; iv) absence of clamping; v) the capability to operate at cryogenic temperatures. Measurements at cryogenic temperatures on SiO2 and at room temperature only on Ta2O5 films deposited on silicon are presented.

Anomalous variable-temperature photoluminescence of CsPbBr3 perovskite quantum dots embedded into an organic solid

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20942-20948 ◽  
Author(s):  
Fei Tang ◽  
Zhicheng Su ◽  
Honggang Ye ◽  
Ye Zhu ◽  
Jiyan Dai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Variable Temperature ◽  
Inorganic Lead ◽  
Organic Solid ◽  
Perovskite Quantum Dots ◽  
Halide Perovskite ◽  
Lead Halide

All-inorganic lead halide perovskite quantum dots (PQDs) of CsPbBr3 were synthesized at room temperature via a facile solution-based procedure. Anomalous variable-temperature photoluminescence of the PQDs embedded into an organic solid was observed.

scholarly journals Optical properties of CuSe thin films - band gap determination

2017 ◽  
Vol 49 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Milica Petrovic ◽  
Martina Gilic ◽  
Jovana Cirkovic ◽  
Maja Romcevic ◽  
Nebojsa Romcevic ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Nir Spectroscopy ◽  
Copper Selenide ◽  
Photoluminescence Spectra ◽  
Indirect Transition ◽  
Direct Transition ◽  
Scanning Electron

Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material.

In2O3 Thin Films Prepared on TiAlN Substrates Using a Triethylindium and Oxygen Mixture

2007 ◽  
Vol 124-126 ◽  
pp. 1597-1600
Author(s):  
Hyoun Woo Kim ◽  
Sun Keun Hwang ◽  
Won Seung Cho ◽  
Tae Gyung Ko ◽  
Seung Yong Choi ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Room Temperature ◽  
Light Emission ◽  
Xrd Analysis ◽  
Oxygen Mixture ◽  
Photoluminescence Spectra ◽  
Sem Images ◽  
Room Temperature Photoluminescence ◽  
Visible Light Emission

This paper reports the fabrication of indium oxide (In2O3) films using a triethylindium and oxygen mixture. The deposition has been carried out on TiAlN substrates (200-350°C). We have established the correlation between the substrate temperature and the structural properties. The films deposited at 300-350°C were polycrystalline, whereas those deposited at 200°C was close to amorphous. XRD analysis and SEM images indicated that the films grown at 350°C had grained structures with the (222) preferred orientation. The room-temperature photoluminescence spectra of the In2O3 films exhibited a visible light emission.

Size-dependent room-temperature luminescence decay from PbS quantum dots

2012 ◽  
Author(s):  
Alexander P. Litvin ◽  
Peter S. Parfenov ◽  
Elena V. Ushakova ◽  
Anatoly V. Fedorov ◽  
Mikhail V. Artemyev ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Luminescence Decay ◽  
Size Dependent ◽  
Pbs Quantum Dots ◽  
Room Temperature Luminescence

scholarly journals Electron glass signatures up to room temperature in disordered insulators

2022 ◽  
Author(s):  
Julien Delahaye ◽  
Thierry Grenet
Keyword(s):  
Thin Films ◽  
Equilibrium State ◽  
Gate Voltage ◽  
Room Temperature ◽  
Cryogenic Temperatures ◽  
Field Effects ◽  
Non Equilibrium

Abstract This paper describes the observation of non-equilibrium field effects at room temperature in four disordered insulating systems: granular Al, discontinuous Au, amorphous NbSi and amorphous InOx thin films. The use of wide enough gate voltage ranges and a cautious analysis of the data allow us to uncover memory dips, the advocated hallmark of the electron glass, in the four systems. These memory dips are found to relax slowly over days of measurements under gate voltage changes, reflecting the impossibility for the systems to reach an equilibrium state within experimentally accessible times. Our findings demonstrate that these electrical glassy effects, so far essentially reported at cryogenic temperatures, actually extend up to room temperature.

Correlation of Size and Photoluminescence for Ge Nanocrystals in SiO2 Matrices

1994 ◽  
Vol 358 ◽  
Author(s):  
C.M Yang ◽  
K.V. Shcheglov ◽  
M.L. Brongersma ◽  
A Polman ◽  
H.A. Atwater
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Room Temperature ◽  
Size Distributions ◽  
Photoluminescence Spectra ◽  
Size Dependent ◽  
Electron Microscopy Data ◽  
Exciton Recombination ◽  
Microscopy Data ◽  
Ge Nanocrystals

ABSTRACTSynthesis and size-dependent photoluminescence has been performed for Ge nanocrystals in SiO2 matrices with average diameters between 2 nm and 9 nm, formed by room temperature ion implantation into SiO2 followed by precipitation during vacuum thermal anneals. Nanocrystal size distributions obtained from electron microscopy data were used in conjunction with a quantum-confined exciton recombination model[l] to generate calculated photoluminescence spectra, which were compared with experimental spectra.

Sign in / Sign up

Export Citation Format

Share Document