scholarly journals Temperature-dependent photoluminescence properties of porous fluorescent SiC

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Weifang Lu ◽  
Abebe T. Tarekegne ◽  
Yiyu Ou ◽  
Satoshi Kamiyama ◽  
Haiyan Ou
Keyword(s):  
Surface Passivation ◽  
Surface States ◽  
Atomic Layer ◽  
Emission Peak ◽  
Photoelectron Spectra ◽  
Porous Structures ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Pl Emission ◽  
Temperature Dependent Photoluminescence

Abstract A comprehensive study of surface passivation effect on porous fluorescent silicon carbide (SiC) was carried out to elucidate the luminescence properties by temperature dependent photoluminescence (PL) measurement. The porous structures were prepared using an anodic oxidation etching method and passivated by atomic layer deposited (ALD) Al2O3 films. An impressive enhancement of PL intensity was observed in porous SiC with ALD Al2O3, especially at low temperatures. At temperatures below 150 K, two prominent PL emission peaks located at 517 nm and 650 nm were observed. The broad emission peak at 517 nm was attributed to originate from the surface states in the porous structures, which was supported by X-ray photoelectron spectra characterization. The emission peak at 650 nm is due to donor-acceptor-pairs (DAP) recombination via nitrogen donors and boron-related double D-centers in fluorescent SiC substrates. The results of the present work suggest that the ALD Al2O3 films can effectively suppress the non-radiative recombination for the porous structures on fluorescent SiC. In addition, we provide the evidence based on the low-temperature time-resolved PL that the mechanism behind the PL emission in porous structures is mainly related to the transitions via surface states.

scholarly journals The thermal stability of FAPbBr3 nanocrystals from temperature-dependent photoluminescence and first-principles calculations

RSC Advances ◽  
2020 ◽  
Vol 10 (72) ◽  
pp. 44373-44381
Author(s):  
Xiaozhe Wang ◽  
Qi Wang ◽  
Zhijun Chai ◽  
Wenzhi Wu
Keyword(s):  
First Principles ◽  
First Principle ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Time Resolved ◽  
First Principle Calculations ◽  
Steady State Time ◽  
Time Resolved Photoluminescence ◽  
Thermal Stability Of ◽  
Temperature Dependent Photoluminescence

The thermal properties of FAPbBr3 perovskite nanocrystals (PNCs) is investigated by use of temperature-dependent steady-state/time-resolved photoluminescence and first-principle calculations.

scholarly journals Light Emission by Nanoporous GaN Produced by a Top-Down, Nonlithographical Nanopatterning

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
E. Kheirandish ◽  
N. A. Kouklin ◽  
J. Liang
Keyword(s):  
Light Emission ◽  
Electronic Devices ◽  
Emission Spectra ◽  
Temperature Dependent ◽  
Physical Mechanisms ◽  
Spectral Shifts ◽  
Nanopore Arrays ◽  
Bulk Gan ◽  
Pl Emission ◽  
Temperature Dependent Photoluminescence

Temperature-dependent photoluminescence (PL) spectroscopy is carried out to probe radiative recombination and related light emission processes in two-dimensional periodic close-packed nanopore arrays in gallium nitride (np-GaN). The arrays were produced by nonlithographic nanopatterning of wurtzite GaN followed by a dry etching. The results of Raman spectroscopy point to a small relaxation of the compressive stress of ~0.24 GPa in nanoporous vs. bulk GaN. At ~300 K, the PL emission is induced by excitons and not free-carrier interband radiative recombinations. An evolution of the emission spectra with T is confirmed to be mainly a result of a decay of nonexcitonic PL emission and less of spectral shifts of the underlying PL bands. A switching of excitonic PL regime observed experimentally was analyzed within the exciton recombination-generation framework. The study provides new insights into the behaviors and physical mechanisms regulating light emission processes in np-GaN, critical to the development of nano-opto-electronic devices based on mesoscopic GaN.

On the Origin of Light Emission in GaNxP1-x

2002 ◽  
Vol 722 ◽  
Author(s):  
I. A. Buyanova ◽  
G. Yu. Rudko ◽  
W. M. Chen ◽  
H. P. Xin ◽  
C. W. Tu
Keyword(s):  
Light Emission ◽  
Multiple Quantum Well ◽  
The Other ◽  
Multiple Quantum ◽  
Optical Transitions ◽  
Temperature Dependent ◽  
Quantum Well Structures ◽  
Pl Emission ◽  
Temperature Dependent Photoluminescence ◽  
Absorption Measurements

AbstractTemperature dependent photoluminescence (PL) and absorption measurements are employed to clarify mechanism for light emission in GaNP alloys with low (< 4.1) nitrogen content. The PL emission in GaNP epilayers and GaNP/GaP multiple quantum well structures is shown to be dominated by optical transitions within deep states likely related to N clusters. With increasing N composition these states are shown to become resonant with conduction band of the alloy and thus optically inactive, leading to the apparent red shift of the PL maximum position. On the other hand, band-to-band recombination in the alloy remains predominantly non-radiative presumably due to the presence of a large number of competing recombination channels.

Investigation of the Electronic Structure of the UD-4 Defect in 4H-SiC by Optical Techniques

2006 ◽  
Vol 527-529 ◽  
pp. 461-464 ◽  
Author(s):  
Aurelie Thuaire ◽  
Anne Henry ◽  
Björn Magnusson ◽  
Peder Bergman ◽  
W.M. Chen ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Electronic Structure ◽  
Low Temperature ◽  
Deep Level ◽  
Temperature Dependent ◽  
Deep Level Defect ◽  
Time Resolved ◽  
Optical And Electronic Properties ◽  
Time Resolved Photoluminescence ◽  
Temperature Dependent Photoluminescence

A detailed investigation of the optical and electronic properties of the deep-level defect UD-4 is reported. This defect has recently been observed in 4H semi-insulating silicon carbide, but has hardly been studied yet. Both low temperature and temperature-dependent photoluminescence were collected from the defect. Zeeman spectroscopy measurements were performed as well as time-resolved photoluminescence.

Detailed Photoluminescence Studies of Heat-Treated InP

1992 ◽  
Vol 262 ◽  
Author(s):  
Klaus Pressel ◽  
C. Hiller ◽  
G. Bohnert ◽  
F. Prinz ◽  
A. Dörnen
Keyword(s):  
Magnetic Field ◽  
Heat Treatment ◽  
Wavelength Range ◽  
Concentration Level ◽  
Field Studies ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Heat Treated ◽  
Photoluminescence Studies ◽  
Temperature Dependent Photoluminescence

ABSTRACTWe present highly resolved photoluminescence studies on heat-treated nominally undoped InP, which was either unprotected or protected by SiO2 or Si3N4 caps during the annealing procedures. Annealing of InP above 350°C leads to six different sharp emissions in the wavelength range between 8790 and 8900 Å, which are not observed at 4 K in Zn-doped or Fe-doped samples. Based on temperature-dependent photoluminescence studies, time-resolved measurements and preliminary magnetic field studies we ascribe these emissions to isoelectronic bound exciton transitions. It is also shown that the two emissions at 8883 Å (11254 cm-1) (E) and 8889 Å (11246 cm-1) (F) belong to one center. We observe that the lines not only depend on the heat treatment but also on some unintentionally incorporated or residual impurities of a low concentration level. Possible candidates are discussed.

Comparative investigation on temperature-dependent photoluminescence of CH3NH3PbBr3and CH(NH2)2PbBr3microstructures

2016 ◽  
Vol 4 (20) ◽  
pp. 4408-4413 ◽  
Author(s):  
Jun Dai ◽  
Hongge Zheng ◽  
Can Zhu ◽  
Junfeng Lu ◽  
Chunxiang Xu
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Comparative Investigation ◽  
Emission Peak ◽  
Red Shift ◽  
Photoluminescence Spectra ◽  
Temperature Dependent ◽  
Exciton Emission ◽  
Temperature Dependent Photoluminescence

Temperature-dependent photoluminescence spectra of CH3NH3PbBr3show that the exciton emission peak continuously blue shifts with the increase in temperature from 10 K to room temperature. CH(NH2)2PbBr3shows a sudden red shift near 150 K due to phase transition.

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