Space and Time Resolved Photoluminescence of Defects at Dislocations in In-Alloyed GaAs Substrate Material

1987 ◽  
Vol 104 ◽  
Author(s):  
Matthew B. Johnson ◽  
A. T. Hunter ◽  
T. C. McGill
Keyword(s):  
Gaas Substrate ◽  
Surface Recombination ◽  
Substrate Material ◽  
Outer Radius ◽  
Time Resolved ◽  
Space And Time ◽  
Dislocation Cluster ◽  
Pl Intensity ◽  
Time Resolved Photoluminescence ◽  
Intensity Contrast

ABSTRACTWe report a study of dislocations in In-alloyed GaAs substrate material using space and time resolved photoluminescence (PL). PL intensity maps show that an isolated dislocation cluster is in the center of a dark region with a 50μm radius surrounded by a bright region with an outer radius of 150μm. Lifetime measurements were made in the bright and dark regions. Values as long as 3.5 ns and as short as 250 psec were observed in adjacent bright and dark regions. These measurements indicate that the PL intensity contrast is explained by lifetime variations in these features. This supports the view that the dislocation cluster acts as a source and sink for defects which govern the lifetime in the surrounding material. Temperature dependence of the lifetime indicates two different defects may be involved. Both of these produce deep levels, neither one of which is EL2. A surface passivation technique is used to show that surface recombination is not important to the PL intensity contrast.

scholarly journals Влияние условий роста и уровня легирования на кинетику люминесценции слоев Ge : Sb, выращенных на кремнии

2020 ◽  
Vol 54 (7) ◽  
pp. 685
Author(s):  
Д.В. Юрасов ◽  
Н.А. Байдакова ◽  
А.Н. Яблонский ◽  
А.В. Новиков
Keyword(s):  
Doping Level ◽  
Room Temperature ◽  
Carrier Lifetime ◽  
Growth Conditions ◽  
Published Data ◽  
Rapid Thermal Anneal ◽  
Time Resolved ◽  
Light Emitting ◽  
Pl Intensity ◽  
Time Resolved Photoluminescence

Light-emitting properties of Ge-on-Si(001) layers doped by Sb were studied by stationary and time-resolved photoluminescence (PL) at room temperature. It was obtained that the PL intensity of n-Ge/Si(001) structures is maximized when the doping level is close to the equilibrium solubility of Sb in Ge (~1019 cm-3) which is in accordance with the previously published data. Time-resolved studies of the direct-related PL signal have shown that both the donor density and the growth conditions of doped layer, in particular, the growth temperature influence the PL kinetics. It was obtained that the increase of doping level leads to the decrease of the characteristic carrier lifetime. Moreover, usage of low growth temperatures which is needed to form the doped n-Ge layers also results in shortening of the carrier lifetime as compared with Ge layers grown at high temperatures. It was found that rapid thermal anneal at proper conditions could partially compensate the above mentioned detrimental effects and lead to the increase of both the PL intensity and carrier lifetime.

scholarly journals Time-resolved photoluminescence on double graded Cu(In,Ga)Se2 – Impact of front surface recombination and its temperature dependence

2019 ◽  
Vol 20 (1) ◽  
pp. 313-323 ◽  
Author(s):  
Thomas Paul Weiss ◽  
Romain Carron ◽  
Max H. Wolter ◽  
Johannes Löckinger ◽  
Enrico Avancini ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Surface Recombination ◽  
Front Surface ◽  
Time Resolved ◽  
Time Resolved Photoluminescence

Excitation-Wavelength Dependent and Time-Resolved Photoluminescence Studies of Europium Doped GaN Grown by Interrupted Growth Epitaxy (IGE)

2005 ◽  
Vol 866 ◽  
Author(s):  
Ei Ei Nyein ◽  
Uwe Hömmerich ◽  
Chanaka Munasinghe ◽  
Andrew J. Steckl ◽  
John M. Zavada
Keyword(s):  
Room Temperature ◽  
Growth Conditions ◽  
Excitation Wavelength ◽  
Time Resolved ◽  
Pl Intensity ◽  
Photoluminescence Studies ◽  
Two Peaks ◽  
Time Resolved Photoluminescence ◽  
Cycling Time ◽  
The Eu

AbstractThe emission properties of Eu doped GaN thin films prepared by interrupted growth epitaxy (IGE) were investigated through excitation-wavelength dependent and time-resolved photoluminescence (PL) studies. Under above-gap excitation (333-363 nm) large differences were observed in the Eu3+ PL intensity and spectral features as a function of Ga shutter cycling time. The overall strongest red Eu3+ PL intensity was obtained from a sample grown with a Gashutter cycling time of 20 minutes. The main Eu3+ emission line originating from 5D0→ 7F2 transition was composed of two peaks located at 620 nm and 622 nm, which varied in relative intensity depending on the growth conditions. The room-temperature emission lifetimes of the samples were non-exponential and varied from ∼50 νs to ∼200 νs (1/e lifetimes). Under resonant excitation at 471 nm (7F0→5D2) all samples exhibited nearly identical PL spectra independent of Ga shutter cycling time. Moreover, the Eu3+ PL intensities and lifetimes varied significantly less compared to above-gap excitation. The excitation wavelengths dependent PL results indicate the existence of different Eu3+ centers in GaN: Eu, which can be controlled by the Ga shutter cycling time.

Role of Tryptophan in Protein–Nanocrystals Interaction: Energy or Charge Transfer

2018 ◽  
Vol 233 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Mona Mittal ◽  
Saurabh Gautam ◽  
Pramit Kumar Chowdhury ◽  
Shashank Deep ◽  
Sameer Sapra
Keyword(s):  
Charge Transfer ◽  
Steady State ◽  
Semiconductor Nanocrystals ◽  
Binding Model ◽  
Time Resolved ◽  
Tryptophan Residues ◽  
Mechanism Of Interaction ◽  
Pl Intensity ◽  
Time Resolved Photoluminescence

Abstract The understanding of the interaction between the semiconductor nanocrystals (NCs) and the proteins are essential for design and fabrication of nanocomposites for application in the field of biotechnology. Herein, we have studied the interaction between CdTe NCs and the proteins by steady-state and time-resolved photoluminescence (PL) spectroscopy. The steady-state PL intensity of CdTe NCs is quenched and enhanced in the presence of lysozyme and bovine serum albumin, respectively. However, the PL intensity of CdTe NCs is not affected with α-synuclein, indicating the role of tryptophan moiety in the protein–NCs interaction. The detailed analysis of PL data allows us to elucidate the dominant mechanism of interaction, i.e. charge or energy transfer, depending on the location of tryptophan residues in the protein. Assuming a Poisson statistic of lysozymes around NCs, the Poisson binding model is used to understand the kinetics of charge transfer from CdTe NCs to the lysozyme. It provides the average number of lysozymes present on the surface of one CdTe NC.

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