Photoluminescence and Sims Studies of Hydrogen Passivation of Mg-Doped P-Type Gallium Nitride

1995 ◽  
Vol 395 ◽  
Author(s):  
Y. Li ◽  
Y. Lu ◽  
H. Shen ◽  
M. Wraback ◽  
C.-Y. Hwang ◽  
...  
Keyword(s):  
Doping Level ◽  
Exciton Peak ◽  
Nonradiative Recombination ◽  
Hydrogen Passivation ◽  
Mg Doping ◽  
Recombination Centers ◽  
Pl Intensity ◽  
P Type ◽  
Secondary Ion ◽  
Mg Doped

ABSTRACTThe effects of hydrogen passivation in MOCVD grown Mg doped p-type GaN were studied using low temperature (5K) photoluminescence (PL) and secondary-ion-mass spectroscopy (SIMS). GaN films with different Mg doping level were annealed at 700° C in N2 ambient with different annealing times. The SIMS results indicate that the hydrogen concentration increases with increasing Mg doping level in the as-grown Mg:GaN film. After 20 minutes of annealing, most of the hydrogen escapes from the film. The 3.455 eV PL peak before annealing and the 3.446 eV peak after annealing found in the Mg doped samples were attributed to the exciton bound to the Mg-H complex and to the Mg acceptor, respectively. The shift of the bound exciton peak to higher energy (3.465 eV) in the lightly doped sample is due to an effective n-type compensation associated with an annealing-induced increase in the nitrogen vacancies. In heavily doped Mg:GaN, the decreases in the integrated PL intensity after 700° C annealing may be associated with the hydrogen depassivation of nonradiative recombination centers in the film. The increase of PL intensity in the lightly doped sample after annealing is attributed to the reduction of defects by the annealing process.

Hydrogen Passivation of Defects in InGaAs/AlxGal-xAs Quantum Wells

1992 ◽  
Vol 262 ◽  
Author(s):  
S. M. Lord ◽  
G. Roos ◽  
B. Pezeshki ◽  
J. S. Harris ◽  
N. M. Johnson
Keyword(s):  
Quantum Wells ◽  
Depth Distribution ◽  
Multilayered Structure ◽  
Nonradiative Recombination ◽  
Hydrogen Passivation ◽  
Defect Passivation ◽  
Recombination Centers ◽  
Pl Intensity ◽  
Secondary Ion

ABSTRACTThe effect of the diffusion of monatomic hydrogen into InGaAs/AlGaAs quantum wells has been investigated using photoluminescence (PL) and Secondary Ion Mass Spectroscopy (SIMS). The structures were grown by molecular beam epitaxy and hydrogenated with a remote plasma. For In0.2Ga0.8AlxGA1-xAs quantum wells, hydrogenation significant increases the integrated PL intensity from bound excitons at 77 K. The enhancement of the PL is ascribed to removal of nonradiative recombination centers by hydrogen passivation of defects either at the heterojunction interface or within the epilayers. This PL enhancement (and defect passivation) increases as the Al concentration in the AlGaAs layers increases from 0 to 33 at%. A 50% increase of PL intensity is observed for InGaAs/GaAs. For 33 at%, the increase is a factor of 9. We also diffused deuterium into these InGaAs/AlGaAs quantum wells. The enhancement of the PL by deuteration was similar to that by hydrogenation. The isotopie substitution permits the determination of the depth distribution of deuterium in the multilayered structure by SIMS. SIMS results support the conclusion that more defects are passivated in the higher Al concentration samples.

Photoluminescence of Pulsed Ruby Laser Annealed Crystalline and Ion Implanted GaAs

1981 ◽  
Vol 4 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Bernard J. Feldman
Keyword(s):  
Radiative Recombination ◽  
Laser Annealing ◽  
Laser Energy ◽  
Pulsed Laser ◽  
High Dose ◽  
Pulsed Laser Annealing ◽  
Recombination Centers ◽  
Pl Intensity ◽  
P Type ◽  
Ion Implanted

ABSTRACTIn an effort to understand the origin of defects earlier found to be present in p–n junctions formed by pulsed laser annealing (PLA) of ion implanted (II) semiconducting GaAs, photoluminescence (PL) studies have been carried out. PL spectra have been obtained at 4K, 77K and 300K, for both n–and p–type GaAs, for laser energy densities 0 ≤ El ≤ 0.6 J/cm2. It is found that PLA of crystalline (c−) GaAs alters the PL spectrum and decreases the PL intensity, corresponding to an increase in density of non-radiative recombination centers with increasing El. The variation of PL intensity with El is found to be different for n– and p–type material. No PL is observed from high dose (1 or 5×1015 ions/cm2 ) Sior Zn-implanted GaAs, either before or after laser annealing. The results suggest that the ion implantation step is primarily responsible for formation of defects associated with the loss of radiative recombination, with pulsed annealing contributing only secondarily.

Intense Photoluminescence and Photoluminescence Enhancement of Silicon Nanocrystals by Ultraviolet Irradiation

2007 ◽  
Vol 31 ◽  
pp. 74-76 ◽  
Author(s):  
P.T. Huy ◽  
P.H. Duong
Keyword(s):  
Silicon Nanocrystals ◽  
Room Temperature ◽  
Laser Excitation ◽  
Uv Light ◽  
Irradiation Time ◽  
Excitation Wavelength ◽  
Nonradiative Recombination ◽  
Emission Yield ◽  
Recombination Centers ◽  
Pl Intensity

Photoluminescence (PL) from silicon nanocrystals deposited on top of silica-glass template and from silicon nanocrystals in nc_Si/SiO2 multilayer films were studied as a function of ultraviolet (UV) laser irradiation time in vacuum. Both the films exhibit intense visible PL at room temperature under laser excitation. It was found that upon prolong irradiation time using a He-Cd laser (325 nm) the PL intensity of the films was spectacularly enhanced. The process is reversible and does not happen with excitation wavelength longer than 400 nm. Upon introducing air into the measurement chamber, a rapid decrease of the PL intensity was recorded. This observation suggests that the UV light may lead to modification of nonradiative recombination centers in the films and thus improves the emission yield of silicon nanocrystals.

scholarly journals Influence of Mg Doping Levels on the Sensing Properties of SnO2 Films

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2158
Author(s):  
Bouteina Bendahmane ◽  
Milena Tomić ◽  
Nour El Houda Touidjen ◽  
Isabel Gràcia ◽  
Stella Vallejos ◽  
...  
Keyword(s):  
Doping Level ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Sno2 Film ◽  
Spray Pyrolysis Method ◽  
Composition Analysis ◽  
Ethanol Sensitivity ◽  
Sensing Properties ◽  
Mg Doping ◽  
Mg Doped

This work presents the effect of magnesium (Mg) doping on the sensing properties of tin dioxide (SnO2) thin films. Mg-doped SnO2 films were prepared via a spray pyrolysis method using three doping concentrations (0.8 at.%, 1.2 at.%, and 1.6 at.%) and the sensing responses were obtained at a comparatively low operating temperature (160 °C) compared to other gas sensitive materials in the literature. The morphological, structural and chemical composition analysis of the doped films show local lattice disorders and a proportional decrease in the average crystallite size as the Mg-doping level increases. These results also indicate an excess of Mg (in the samples prepared with 1.6 at.% of magnesium) which causes the formation of a secondary magnesium oxide phase. The films are tested towards three volatile organic compounds (VOCs), including ethanol, acetone, and toluene. The gas sensing tests show an enhancement of the sensing properties to these vapors as the Mg-doping level rises. This improvement is particularly observed for ethanol and, thus, the gas sensing analysis is focused on this analyte. Results to 80 ppm of ethanol, for instance, show that the response of the 1.6 at.% Mg-doped SnO2 film is four times higher and 90 s faster than that of the 0.8 at.% Mg-doped SnO2 film. This enhancement is attributed to the Mg-incorporation into the SnO2 cell and to the formation of MgO within the film. These two factors maximize the electrical resistance change in the gas adsorption stage, and thus, raise ethanol sensitivity.

scholarly journals Photoluminescence Characterization of Nonradiative Recombination Centers in Light Emitting Materials by Utilizing Below-Gap Excitation: A Mini Review of Two-Wavelength Excited Photoluminescence

2015 ◽  
Vol 43 ◽  
pp. 1-9
Author(s):  
Norihiko Kamata ◽  
Abu Zafor Md. Touhidul Islam
Keyword(s):  
Quantum Wells ◽  
Electrical Contact ◽  
Intensity Change ◽  
Nonradiative Recombination ◽  
Excitation Light ◽  
Light Emitting ◽  
Recombination Centers ◽  
Pl Intensity ◽  
Trap Filling

We have developed an optical method of detecting and characterizing nonradiative recombination (NRR) centers without electrical contact. The method combines a below-gap excitation (BGE) light with a conventional above-gap excitation light in photoluminescence (PL) measurement, and discriminates the PL intensity change due to switching on and off the BGE. A quantitative analysis of the detected NRR centers became possible by utilizing the saturating tendency of the PL intensity change with increasing the BGE density due to trap filling effect. Some experimental results of AlGaAs, InGaN, and AlGaN quantum wells were shown to allocate the development and present status as well as to exemplify their interpretations.

Secondary ion mass spectrometry study of Ti4+diffusion properties in congruent Er:LiNbO3codoped with moderate concentration of MgO

2009 ◽  
Vol 24 (10) ◽  
pp. 3057-3064 ◽  
Author(s):  
De-Long Zhang ◽  
Bei Chen ◽  
Liang Sun ◽  
Yu-Heng Xu ◽  
Edwin Yue-Bun Pun
Keyword(s):  
Mass Spectrometry ◽  
Doping Level ◽  
Secondary Ion Mass Spectrometry ◽  
Gaussian Function ◽  
Mg Doping ◽  
Mass Spectrometry Study ◽  
Ion Mass Spectrometry ◽  
Profile Characteristics ◽  
Secondary Ion ◽  
Diffusion Properties

At 1100 °C, the diffusion properties of Ti4+into congruent LiNbO3crystals codoped with 0.5 mol% Er2O3and different MgO concentrations of 0.5, 1.0, and 1.5 mol% have been studied by secondary ion mass spectrometry (SIMS). ThreeY-cut and threeZ-cut plates with different Mg doping levels were coated with a 60-nm-thick Ti film at first and then annealed at 1100 °C for 28 h in a wet O2atmosphere. SIMS was used to analyze depth profile characteristics of diffused Ti ions and the constituent elements of the substrate as well. The results show that the diffusion reservoir was exhausted and the Ti metal film was completely diffused. All measured Ti profiles follow a Gaussian function. No Mg out-diffusion accompanied the Ti in-diffusion procedure for all crystals studied. The 1/ediffusion depth is similar to 8.3/10.2, 7.4/8.7, and 6.6/8.2 ± 0.2/0.2 μm/μm for theY/Z-cut crystal with the Mg doping level of 0.5, 1.0, and 1.5 mol%, respectively, yielding a Ti4+diffusivity of 0.62/0.93, 0.49/0.67, and 0.39/0.60 ± 0.03/0.03 (μm2/h)/(μm2/h), respectively. The diffusion shows definite anisotropy and a considerable MgO doping level effect. Under the same Mg doping level, the diffusion in aZ-cut crystal is faster. The diffusivity decreases with the increase of the Mg doping level. This effect is qualitatively explained from the viewpoint of the Mg doping effect on concentration of the intrinsic defects in LiNbO3crystal.

Epitaxial Growth and Properties of Mg-Doped Gan Film Produced by Atmospheric Mocvd System With Three Layered Lammar Flow Gas Injection

1997 ◽  
Vol 482 ◽  
Author(s):  
N. Akutsu ◽  
H. Tokunaga ◽  
I. Waki ◽  
A. Yamaguchi ◽  
K. Matsumoto
Keyword(s):  
Thermal Annealing ◽  
Room Temperature ◽  
Hole Concentration ◽  
Gas Injection ◽  
Chemical Vapor ◽  
Free Hole ◽  
Mg Doping ◽  
Doping Effects ◽  
P Type ◽  
Mg Doped

AbstractMg-doped GaN films with a variety of Mg concentrations were grown on sapphire (0001) by horizontal atmospheric metalorganic chemical vapor deposition (MOCVD) system with three layered laminar flow gas injection in an attempt to study the Mg doping effects on film quality. The increase of Mg concentration induced an increase of x-ray rocking curve full width at half maximum (FWHM) and degradation of surface morphology. Secondary ion mass spectroscopy (SIMS) analysis shows increase of Si and O, associated with Mg-doping concentration. Si and O concentrations of Mg-doped film are up to 5×1016cm−3 and 5×1017cm−3 at Mg concentration of 4.5×1019cm−3, respectively. Strong 380nm emission and weak 430nm emission were observed by photoluminescence (PL) measurement at room temperature for as-grown Mg-doped GaN films which shows p-type conductivity after thermal annealing. While, in highliy Mg-doped GaN films which do not show the p-type conduction after thermal annealing, 430nm and/or 450nm emission were dominating. The highest room temperature free hole concentration achieved was p=2.5× 1018cm−3 with mobility μp=l.9cm2/V s.

Hydrogen Passivation of Si and Be Dopants in InAlAs

1991 ◽  
Vol 240 ◽  
Author(s):  
G. Roos ◽  
N. M. Johnson ◽  
Y. C. Pao ◽  
J. S. Harris ◽  
C.y Herring
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Microwave Plasma ◽  
Hydrogen Passivation ◽  
Electrical Measurements ◽  
Annealing Step ◽  
Si Doped ◽  
P Type ◽  
Secondary Ion ◽  
Limited Process

ABSTRACTHydrogen passivation and thermal reactivation of Si donors and Be acceptors were investigated in In0.52Al0.48As grown by molecular beam epitaxy. The semiconducting alloy was passivated by exposure to monatomic hydrogen or deuterium from a remote microwave plasma. The passivation was achieved by exposing the samples to monatomic hydrogen at temperatures between 200 and 250 °C for 1h. The electrical activity of the dopants was monitored by spreading resistance and C-V measurements. The samples were homogeneously doped to concentrations of 1.5×1016 or 6×1017 Si / cm3 and 6×1017 Be / cm3. Both dopants were passivated by more than two orders of magnitude through the epitaxial layers. An additional annealing step (440°C, 5 min) resulted in a complete reactivation of the passivated dopants. In addition to the electrical measurements, secondary ion mass spectroscopy showed that for both the Be- and the Si-doped layers the hydrogen profiles were essentially identical to the dopant profiles throughout the epilayers. This behaviour suggests that hydrogen migration is a dopant-trapping-limited process in n-and p-type In0.52Al0.48As.

scholarly journals Effects of NH3 Plasma and Mg Doping on InGaZnO pH Sensing Membrane

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 994
Author(s):  
Chyuan-Haur Kao ◽  
Chia-Shao Liu ◽  
Shih-Ming Chan ◽  
Chih-Chen Kuo ◽  
Shang-Che Tsai ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ph Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mg Doping ◽  
Transmission Electron ◽  
Multiple Material ◽  
Sensing Membrane ◽  
Secondary Ion ◽  
Mg Doped

In this study, the effects of magnesium (Mg) doping and Ammonia (NH3) plasma on the pH sensing capabilities of InGaZnO membranes were investigated. Undoped InGaZnO and Mg-doped pH sensing membranes with NH3 plasma were examined with multiple material analyses including X-ray diffraction, X-ray photoelectron spectroscopy, secondary ion mass spectroscopy and transmission electron microscope, and pH sensing behaviors of the membrane in electrolyte-insulator-semiconductors. Results indicate that Mg doping and NH3 plasma treatment could superpositionally enhance crystallization in fine nanostructures, and strengthen chemical bindings. Results indicate these material improvements increased pH sensing capability significantly. Plasma-treated Mg-doped InGaZnO pH sensing membranes show promise for future pH sensing biosensors.

Effect of Nitrogen Flux on the Properties of N-Doped Zn1-xMgxO Thin Films

2017 ◽  
Vol 900 ◽  
pp. 83-88
Author(s):  
Wei Wei Liu ◽  
Cheng Lin Liu ◽  
Hong Xia Chen ◽  
Rong Wang
Keyword(s):  
Thin Films ◽  
Hole Concentration ◽  
Growth Conditions ◽  
Emission Peak ◽  
Nonradiative Recombination ◽  
Nitrogen Flux ◽  
Uv Emission ◽  
Recombination Centers ◽  
P Type ◽  
Mg Content

Different Mg content in Zn1-xMgxO was also obtained by varying N2 flux. UV emission peak in photoluminescence (PL) spectra shift from 350 nm to 360 nm, and then to 352 nm, which is consistent with the result of absorption spectra of the Zn1-xMgxO:N films grown at different N2 flux. The emission intensity of the Zn1-xMgxO:N band edge peak was drastically reduced with increasing N2 flux, which was attributed to the concentration of nonradiative recombination centers increased with increasing N2 flux. The carrier concentration of N-doped Zn1-xMgxO increased with increasing N2 flux below 0.8 sccm, while those above 0.8 sccm decreased. The p-type Zn1-xMgxO:N with the maximum hole concentration 3.97×1017 cm-3 was obtained by optimizing growth conditions.

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