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.

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.

Epitaxial Growth and Luminescence Characterization of Si-based Double Heterostructures Light-emitting Diodes with Iron Disilicide Active Region

2006 ◽  
Vol 958 ◽  
Author(s):  
Takashi Suemasu ◽  
Cheng Li ◽  
Tsuyoshi Sunohara ◽  
Yuta Ugajin ◽  
Ken'ichi Kobayashi ◽  
...  
Keyword(s):  
Decay Time ◽  
Room Temperature ◽  
Time Resolved ◽  
Iron Disilicide ◽  
Light Emitting ◽  
Si Substrates ◽  
Carrier Recombination ◽  
Double Heterostructures ◽  
Time Resolved Photoluminescence

ABSTRACTWe have epitaxially grown Si/β-FeSi2/Si (SFS) structures with β-FeSi2 particles or β-FeSi2 continuous films on Si substrates by molecular beam epitaxy (MBE), and observed 1.6 μm electroluminescence (EL) at room temperature (RT). The EL intensity increases with increasing the number of β-FeSi2 layers. The origin of the luminescence was discussed using time-resolved photoluminescence (PL) measurements. It was found that the luminescence originated from two sources, one with a short decay time (τ∼10 ns) and the other with a long decay time (τ∼100 ns). The short decay time was due to carrier recombination in β-FeSi2, whereas the long decay time was due probably to a defect-related D1 line in Si.

scholarly journals Time-Resolved Spectroscopy of InGaN

2000 ◽  
Vol 5 (S1) ◽  
pp. 803-809
Author(s):  
Milan Pophristic ◽  
Frederick H. Long ◽  
Chuong Tran ◽  
Ian T. Ferguson
Keyword(s):  
Quantum Dots ◽  
Time Scale ◽  
Room Temperature ◽  
Average Distance ◽  
Time Resolved ◽  
Light Emitting ◽  
Potential Fluctuations ◽  
Stretched Exponential ◽  
Time Resolved Photoluminescence ◽  
Kinetics Of

We have used time-resolved photoluminescence (PL), with 400 nm (3.1 eV) excitation, to examine InxGa1−xN/GaN light-emitting diodes (LEDs) before the final stages of processing at room temperature. We have found dramatic differences in the time-resolved kinetics between dim, bright and super bright LED devices. The lifetime of the emission for dim LEDs is quite short, 110 ± 20 ps at photoluminescence (PL) maximum, and the kinetics are not dependent upon wavelength. This lifetime is short compared to bright and super bright LEDs, which we have examined under similar conditions. The kinetics of bright and super bright LEDs are clearly wavelength dependent, highly non-exponential, and are on the nanosecond time scale (lifetimes are in order of 1 ns for bright and 10 ns for super bright LED at the PL max). The non-exponential PL kinetics can be described by a stretched exponential function, indicating significant disorder in the material. Typical values for β, the stretching coefficient, are 0.45 − 0.6 for bright LEDs, at the PL maxima at room temperature. We attribute this disorder to indium alloy fluctuations.From analysis of the stretched exponential kinetics we estimate the potential fluctuations to be approximately 75 meV in the super bright LED. Assuming a hopping mechanism, the average distance between indium quantum dots in the super bright LED is estimated to be 20 Å.

scholarly journals Minority Carrier Lifetime Measurements on 4H-SiC Epiwafers by Time-Resolved Photoluminescence and Microwave Detected Photoconductivity

2019 ◽  
Vol 963 ◽  
pp. 313-317
Author(s):  
Jan Beyer ◽  
Nadine Schüler ◽  
Jürgen Erlekampf ◽  
Birgit Kallinger ◽  
Patrick Berwian ◽  
...  
Keyword(s):  
Room Temperature ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Temperature Dependent ◽  
Lifetime Measurements ◽  
Time Resolved ◽  
Excess Carrier ◽  
Time Resolved Photoluminescence ◽  
Different Thickness

Temperature dependent microwave detected photoconductivity MDP and time-resolved photoluminescence TRPL were employed to investigate the carrier lifetime in CVD grown 4H-SiC epilayers of different thickness. The minority carrier lifetime may be found from both theMDP and defect PL decay at room temperature for all epilayers, whereas the near bandedge emission (NBE) decay is much faster for thin epilayers (<17 μm) due to the substrate proximity and only follows the minority carrier lifetime for thicker samples at lower excess carrier concentrations.

Elimination of Basal Plane Dislocations in Epitaxial 4H-SiC via Multicycle Rapid Thermal Annealing

2015 ◽  
Vol 821-823 ◽  
pp. 297-302 ◽  
Author(s):  
Marko J. Tadjer ◽  
Nadeemullah A. Mahadik ◽  
Boris N. Feigelson ◽  
Robert E. Stahlbush ◽  
Eugene A. Imhoff ◽  
...  
Keyword(s):  
Basal Plane ◽  
Carrier Lifetime ◽  
Base Temperature ◽  
Rapid Thermal Anneal ◽  
Time Resolved ◽  
Force Microscopy ◽  
Atomic Force ◽  
Photoluminescence Decay ◽  
Before And After ◽  
Time Resolved Photoluminescence

Elimination of basal plane dislocations (BPDs) in epitaxial 4H-SiC is demonstrated via a novel pulsed annealing technique in a moderate N2overpressure of 0.55 MPa. BPD removal in 15 µm thick epitaxial 4H-SiC was confirmed using ultraviolet photoluminescence (UVPL) imaging before and after the annealing process. The samples were capped with a carbon cap, introduced into the annealing chamber, and brought up to a base temperature (TBASE) of around 1550 °C for the pulsed anneal. The multicycle rapid thermal anneal (MRTA) was then performed in the TBASE:TMAXrange, where TMAX= 1875 °C was the peak temperature reached by the annealing cycles. Post-anneal surface quality and carrier lifetime were characterized by atomic force microscopy and time-resolved photoluminescence decay.

scholarly journals Photoluminescence Enhancement in Nanotextured Fluorescent SiC Passivated by Atomic Layer Deposited Al2O3 Films

2016 ◽  
Vol 858 ◽  
pp. 493-496
Author(s):  
Wei Fang Lu ◽  
Yi Yu Ou ◽  
Valdas Jokubavicius ◽  
Ahmed Fadil ◽  
Mikael Syväjärvi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Carrier Lifetime ◽  
Light Emission ◽  
Atomic Layer ◽  
Strong Indication ◽  
Time Resolved ◽  
White Leds ◽  
Result Show ◽  
Photoluminescence Enhancement ◽  
Time Resolved Photoluminescence

The influence of thickness of atomic layer deposited Al2O3 films on nanotextured fluorescent 6H-SiC passivation is investigated. The passivation effect on the light emission has been characterized by photoluminescence and time-resolved photoluminescence at room temperature. The results show that 20nm thickness of Al2O3 layer is favorable to observe a large photoluminescence enhancement (25.9%) and long carrier lifetime (0.86ms). This is a strong indication for an interface hydrogenation that takes place during post-thermal annealing. These result show that an Al2O3 layer could serve as passivation in fluorescent SiC based white LEDs applications.

Time-Resolved Spectroscopy of InGaN

1999 ◽  
Vol 595 ◽  
Author(s):  
Milan Pophristic ◽  
Frederick H. Long ◽  
Chuong Tran ◽  
Ian T. Ferguson
Keyword(s):  
Quantum Dots ◽  
Time Scale ◽  
Room Temperature ◽  
Average Distance ◽  
Time Resolved ◽  
Light Emitting ◽  
Potential Fluctuations ◽  
Stretched Exponential ◽  
Time Resolved Photoluminescence ◽  
Kinetics Of

AbstractWe have used time-resolved photoluminescence (PL), with 400 nm (3.1 eV) excitation, to examine InxGa1−xN/GaN light-emitting diodes (LEDs) before the final stages of processing at room temperature. We have found dramatic differences in the time-resolved kinetics between dim, bright and super bright LED devices. The lifetime of the emission for dim LEDs is quite short, 110 ± 20 ps at photoluminescence (PL) maximum, and the kinetics are not dependent upon wavelength. This lifetime is short compared to bright and super bright LEDs, which we have examined under similar conditions. The kinetics of bright and super bright LEDs are clearly wavelength dependent, highly non-exponential, and are on the nanosecond time scale (lifetimes are in order of 1 ns for bright and 10 ns for super bright LED at the PL max). The non-exponential PL kinetics can be described by a stretched exponential function, indicating significant disorder in the material. Typical values for β, the stretching coefficient, are 0.45 – 0.6 for bright LEDs, at the PL maxima at room temperature. We attribute this disorder to indium alloy fluctuations.From analysis of the stretched exponential kinetics we estimate the potential fluctuations to be approximately 75 meV in the super bright LED. Assuming a hopping mechanism, the average distance between indium quantum dots in the super bright LED is estimated to be 20 Å.

ZnCdO/ZnMgO and ZnO/AlGaN Heterostructures for UV and Visible Light Emitters

2005 ◽  
Vol 892 ◽  
Author(s):  
Andrei Osinsky ◽  
Jianwei Dong ◽  
J. Q. Xie ◽  
B. Hertog ◽  
A. M. Dabiran ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Compositional Analysis ◽  
Optical Emission ◽  
Rf Plasma ◽  
Light Emitters ◽  
Time Resolved ◽  
Light Emitting ◽  
Spatially Resolved ◽  
Time Resolved Photoluminescence ◽  
Made In

AbstractThis paper reviews of some of the progress made in the development of ZnO-based light emitting diodes (LEDs). n-ZnO/p-AlGaN-based heterostructures have been successfully for the fabrication of UV emitting LEDs that have operated at temperatures up to 650K, suggesting an excitonic origin for the optical transitions. RF-plasma-assisted molecular beam epitaxy has been used to grow epitaxial CdxZn1-xO films on GaN/sapphire structure. These films have a single-crystal wurtzite structure as demonstrated by structural and compositional analysis. High quality CdxZn1-xO films were grown with up to x=0.78 mole fraction as determined by RBS and SIMS techniques. Optical emission ranging from purple (Cd0.05Zn0.95O) to yellow (Cd0.29Zn0.71O) was observed. Compositional fluctuations in a Cd0.16Zn0.84O films were not detected by spatially resolved CL measurements, although intensity fluctuation with features of ∼0.5 μm diameter were seen on the intensity maps. Time resolved photoluminescence shows multi-exponential decay with 21 psec. and 49±3 psec. lifetimes, suggesting that composition micro-fluctuations may be present in Cd0.16Zn0.84O film.

On Applicability of Time-Resolved Optical Techniques for Characterization of Differently Grown 3C-SiC Crystals and Heterostructures

2012 ◽  
Vol 711 ◽  
pp. 159-163 ◽  
Author(s):  
Patrik Ščajev ◽  
Pavels Onufrijevs ◽  
Georgios Manolis ◽  
Mindaugas Karaliūnas ◽  
Saulius Nargelas ◽  
...  
Keyword(s):  
Room Temperature ◽  
Defect Density ◽  
Growth Conditions ◽  
Free Carrier ◽  
Band Edge Emission ◽  
Free Carrier Absorption ◽  
Free Standing ◽  
Optical Techniques ◽  
Time Resolved ◽  
Photoelectrical Properties

We applied a number of time-resolved optical techniques for investigation of optical and photoelectrical properties of cubic SiC grown by different technologies on different substrates. The excess carriers were injected by a short laser pulse and their dynamics was monitored by free-carrier absorption, light-induced transient grating, and photoluminescence techniques in a wide excitation range. Combining an optical and electrical probe beam delay, we found that free carrier lifetimes in differently grown layers vary from few ns up to 20 μs. Temperature dependences of carrier diffusivity and lifetime revealed a pronounced carrier trapping in thin sublimation grown layers. In free-standing layers and thick sublimation layers, the ambipolar mobility was found the highest (120 cm2/Vs at room temperature). A linear correlation between the room-temperature band edge emission and carrier lifetime in differently grown layers was attributed to defect density, strongly dependent on the used growth conditions.

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