共查询到20条相似文献,搜索用时 15 毫秒
1.
M.M. Pociask 《Opto-Electronics Review》2010,18(3):338-341
Of many techniques used to characterize quality of HgCdTe, ion milling is emerging as a unique means to reveal electrically
active and neutral defects and complexes. Ion milling is capable of strongly affecting electrical properties of HgCdTe, up
to conductivity type conversion in p-type material. It appears, that strongly non-equilibrium processes which take place under
ion milling, when material is oversaturated with mercury interstitial atoms generated near a surface, lead to formation of
specific defect complexes, which may not form under other type of treatment. By measuring parameters of a crystal before and
after milling, and following disintegration of defects with time after ion milling (’relaxation’), one can detect and identify
these defects. This method was applied to analyse different samples grown by molecular beam epitaxy. 相似文献
2.
I. I. Izhnin A. I. Izhnin H. V. Savytskyy O. I. Fitsych N. N. Mikhailov V. S. Varavin S. A. Dvoretsky Yu. G. Sidorov K. D. Mynbaev 《Opto-Electronics Review》2012,20(4):375-378
The Hall effect and photoluminescence measurements combined with annealing and/or ion milling were used to study the electrical and optical properties of HgCdTe films grown by molecular-beam epitaxy on GaAs substrates with ZnTe and CdTe buffer layers. Unintentional donor doping, likely from the substrate, which resulted in residual donor concentration of the order of 1015 cm?3, was observed in the films. Also, acceptor states, possibly related to structural defects, were observed. 相似文献
3.
I. I. Izhnin H. V. Savytskyy O. I. Fitsych J. Piotrowski K. D. Mynbaev 《Opto-Electronics Review》2013,21(2):220-226
Electrical properties of HgCdTe films grown by metal-organic chemical vapour deposition (MOCVD) on GaAs substrates and doped with the As acceptor during the growth were studied. Discrete mobility spectrum analysis was used to extract the parameters of the as-grown films and films after ion milling and during prolonged relaxation of milling-induced defects. The measurements revealed significant compensation of the as-grown MOCVD HgCdTe with As on Te sites being the main defect, residual donor concentration of the order of (2–5)×1015 cm?3, and the presence of some unidentified defects. 相似文献
4.
V. L. Komolov 《Technical Physics》1997,42(5):499-503
An investigation is made of the conditions for the nucleation of optical breakdown in transparent material when recombination-stimulated
defect-formation reactions occur in it. It is shown that a positive feedback between the conduction electron concentration
and point defects activates defect formation even if the medium is not heated. Under real conditions, where heating of the
medium by the light is important, lowering of the activation barrier by thermal defect generation aided by conduction electrons
results in optical breakdown of the medium at light intensities much lower than predicted in the classical “semiconductor”
or “thermochemical” models of thermal breakdown. The analysis confirms that optical breakdown of transparent condensed media
is due to electron-aided defect formation reactions over a broad range of illumination conditions.
Zh. Tekh. Fiz. 67, 48–53 (May 1997) 相似文献
5.
O. B. Gusev E. I. Terukov Yu. K. Undalov K. D. Tsendin 《Physics of the Solid State》2011,53(2):256-262
The intrinsic defect photoluminescence of hydrogenated amorphous silicon (a-Si:H) films has been investigated at high intensities of optical pumping that lead to heating of the film. It has been revealed
that, for short heating times, the intensity of the defect photoluminescence increases exponentially with an increase in the
temperature with an activation energy of 0.85 eV, which is considerably higher than the activation energy (∼0.2 eV) determined
from experiments on classical annealing. This and other experimental results on the temperature dependence of the intensity
and kinetics of the defect photoluminescence have been explained in terms of the “hydrogen glass” model by thermally induced
generation of intrinsic defects in amorphous silicon. The results of the calculations are in good agreement with the experimental
data on the defect photoluminescence that reflects the formation and annihilation of defects for short heating times under
optical excitation. 相似文献
6.
A. V. Mudryi A. V. Ivanyukovich A. V. Korotkii V. V. Emtsev M. V. Yakushev 《Journal of Applied Spectroscopy》2006,73(1):95-98
Using photoluminescence and transmission measurements, we have studied the optical properties of indium nitride powder and
thin films grown by molecular beam epitaxy. The bandgap for InN powder with electron concentration ∼ 4·1019 cm−3 was 0.94 eV, and for InN films with electron concentrations ∼1018 cm−3 it was 0.7 eV. We have established that when the electron concentration is increased to 8·1019 cm−3, the bandgap of InN increases to 1.0 eV. The change in the bandgap as a function of the concentration is due to the appearance
of the Burstein-Moss effect.
Report given at the Fifth Belorussian-Russian Seminar on Semiconductor Lasers and Systems Based on Semiconductor Lasers, June
1–5, 2005, Minsk, Belarus.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 86–89, January–February, 2006. 相似文献
7.
P.?Madejczyk A.?Piotrowski K.?K?os W.?Gawron J.?Rutkowski A.?Rogalski 《Opto-Electronics Review》2010,18(3):271-276
The acceptor doping of mercury cadmium telluride (HgCdTe) layers grown by MOCVD are investigated. (111)HgCdTe layers were
grown on (100)GaAs substrates at 350°C using horizontal reactor and interdiffused multilayer process (IMP). TDMAAs and AsH3
were alternatively used as effective p-type doping precursors. Incorporation and activation rates of arsenic have been studied.
Over a wide range of Hg1−xCdxTe compositions (0.17 < x < 0.4), arsenic doping concentration in the range from 5×1015 cm−3 to 5×1017 cm−3 was obtained without postgrowth annealing. The electrical and chemical properties of epitaxial layers are specified by measurements
of SIMS profiles, Hall effect and minority carrier lifetimes. It is confirmed that the Auger-7 mechanism has decisive influence
on carrier lifetime in p-type HgCdTe epilayers. 相似文献
8.
Yu. V. Zorenko V. P. Savchin V. I. Gorbenko T. I. Voznyak T. E. Zorenko V. M. Puzikov A. Ya. Dan’ko S. V. Nizhankovskii 《Physics of the Solid State》2011,53(8):1620-1625
Luminescence and scintillation properties of Y3Al5O12:Ce single crystals grown from the melt by the Czochralski and horizontal directed crystallization methods in various gas
media and Y3Al5O12:Ce single-crystal films grown by liquid-phase epitaxy from a melt solution based on a PbO-B2O3 flux have been comparatively analyzed. The strong dependence of scintillation properties of Y3Al5O12:Ce single crystals on their growth conditions and concentrations of YAl antisite defects and vacancy defects has been established. Vacancy defects are involved in Ce3+ ion emission excitation as the centers of intrinsic UV luminescence and trapping centers. It has been shown that Y3Al5O12:Ce single-crystal films are characterized by faster scintillation decay kinetics than single crystals and a lower content
of slow components in Ce3+ ion luminescence decay during high-energy excitation due to the absence of YAl antisite defects in them and low concentration of vacancy defects. At the same time, the light yield of Y3Al5O12:Ce single-crystal films is comparable to that of single crystals grown by directed crystallization due to the quenching effect
of the Pb2+ ion impurity as a flux component and is slightly lower (∼25%) than the light yield of single crystals grown by the Czochralski
method. 相似文献
9.
GaSb single crystals were grown by the Czochralski method without encapsulant in an atmosphere of ionized hydrogen. It has
been found that the resistivity increased by more than one order of magnitude (0.8–1.0Ω cm) and free carrier concentration
decreased to the value of (1–2) × 1016 cm−3 in comparison with the crystals grown under molecular hydrogen atmosphere. A certain asymmetry in acceptor and donor passivation
is assumed because the Hall concentration does not vary along the direction of crystal growth. Donors are passivated more
than acceptors, which should be confirmed by increasing resistivity and decreasing mobility.
Presented at the 6th Joint Seminar “Development of Materials Science in Research and Education”, Karlštejn, Czech Republic,
17–19 September 1996. 相似文献
10.
Preparation, material characterization, ion transport and battery discharge characteristic studies are reported for a new
silver molybdate glass system: x[0.75AgI: 0.25AgCl]: (1-x)[Ag2O: MoO3], where 0<x<1 in molar weight fraction. The traditional host AgI has been replaced by an alternate compound: “a quenched
[0.75AgI: 0.25 AgCl] mixed system/solid solution”. Electrical conductivity (σ), ionic mobility (μ) and mobile ion concentration
(n) measurements were carried out as a function of “x”. The composition: 0.8[0.75AgI: 0.25AgCl]: 0.2[Ag2O: MoO3] exhibited the highest conductivity (∼ 6×10−3 S·cm−1) at room temperature and has been referred to as ‘optimum conducting composition (OCC)’. The compositional variation of “μ”
and “n” revealed that the enhancement in the room temperature conductivity of OCC is predominantly due to the increase in
mobile ion concentration. The XRD and DSC analysis on OCC indicated the formation of glassy phase with partial presence of
unreacted polycrystalline phase of the host salt. The temperature dependence of various ionic transport parameters viz. “σ”,
“μ”, “n” and ionic transference number (tion) were carried out on the OCC and the results have been discussed on the basis of theoretical models suggested for superionic
glasses. In addition to this, solid state batteries were fabricated using OCC as electrolyte and discharge characteristics
were studied under varying load conditions. 相似文献
11.
I.I. Izhnin K.D. Mynbaev A.V. Voitsekhovskii A.G. Korotaev O.I. Fitsych M. Pociask-Bialy 《Opto-Electronics Review》2017,25(2):148-170
Analysis is performed of the contemporary views on the effect of ion etching (ion-beam milling and reactive ion etching) on physical properties of HgCdTe and on the mechanisms of the processes responsible for modification of these properties under the etching. Possibilities are discussed that ion etching opens for defect studies in HgCdTe, including detecting electrically neutral tellurium nanocomplexes, determining background donor concentration in the material of various origins, and understanding the mechanism of arsenic incorporation in molecular-beam epitaxy-grown films. 相似文献
12.
T. Dobrowolski 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):269-271
The production of topological defects during a quench in a φ4 model is investigated. The influence of a spatially correlated noise on defect production in two and three dimensions is
demonstrated.
Received 28 August 2001 / Received in final form 11 February 2002 Published online 2 October 2002
RID="a"
ID="a"Paper supported in part by ESF “COSLAB” Programme
RID="b"
ID="b"e-mail: sfdobrow@kinga.cyf-kr.edu.pl 相似文献
13.
C.F. Zhu W.K. Fong B.H. Leung C. Surya 《Applied Physics A: Materials Science & Processing》2001,72(4):495-497
High-quality GaN thin films are grown by rf-plasma assisted molecular beam epitaxy. The quality of the GaN epitaxial layer
is significantly improved by using an intermediate-temperature GaN buffer layer (ITBL) in addition to a conventional 20-nm-thick
low-temperature buffer layer. The GaN epitaxial layers demonstrate systematic improvements in the electron mobility increasing
from 82 cm2 V-1 s-1, for films grown with just the low-temperature buffer layer, to about 380 cm2 V-1 s-1 for films grown with an ITBL of thickness 800 nm. The photoluminescence also indicates systematic improvements in the intensity
and the full-width-half-maximum with the use of ITBL. Photoreflectance spectra are measured from the GaN films. Detailed analyses
of the excitonic transition energy demonstrate that the residual strain relaxes rapidly with the use of ITBL, which is attributed
to the observed improvements in the mobility and the PL spectra.
Received: 30 November 2000 / Accepted: 4 December 2000 / Published online: 9 February 2001 相似文献
14.
A. V. Voitsekhovskii S. N. Nesmelov S. M. Dzyadukh V. S. Varavin S. A. Dvoretskii N. N. Mikhailov Yu. G. Sidorov V. V. Vasil’ev T. I. Zakhar’yash Yu. P. Mashukov 《Russian Physics Journal》2006,49(10):1117-1128
Voltage, frequency, and temperature dependences of photo-emf are experimentally studied in the MIS HgCdTe/SiO
2
/Si
3
N
4
and HgCdTe/AOF structures. The MIS structures were produced on the basis of graded-bandgap Hg
1−x
Cd
x
Te films grown by molecular-beam epitaxy on GaAs substrates. It is found that the subsurface graded-band-gap layers do affect the photoelectrical characteristics of MIS structures.
The mechanisms limiting the differential resistance in the space-charge region at various temperatures are revealed.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 70–80, October, 2006. 相似文献
15.
D.M. Hofmann D. Pfisterer J. Sann B.K. Meyer R. Tena-Zaera V. Munoz-Sanjose T. Frank G. Pensl 《Applied Physics A: Materials Science & Processing》2007,88(1):147-151
As-grown ZnO bulk crystals and crystals annealed in vacuum, oxygen, or zinc vapour were characterized by electrical, optical
and magnetic resonance spectroscopy. The experiments show that the residual carrier concentration is caused by residual H,
Al, Ga and oxygen vacancies (VO) in the material. Annealing the samples in O2 at about 1000 °C (2 atm, 20 h) reduces the H and VO donor concentration by typically one order of magnitude. The photoluminescence and deep level transient spectroscopy (DLTS)
results suggest a correlation between the broad unstructured emission at 2.45 eV (“green band”) and a donor level 530 meV
below the conduction band, it is attributed to the VO
0/++transition. By using DLTS experiments with optical excitation it is possible to observe a metastable level 140 meV below the
conduction band which is assigned to the VO
2+/+ recharging. The results give evidence for the “negative-U” properties of the oxygen vacancy defects predicted by recent theoretical
calculations.
PACS 71.55.Gs; 72.20.Jv; 76.30.Mi; 76.70.Hb; 78.55.Et 相似文献
16.
V. N. Berzhanskiĭ A. I. Gorbovanov S. N. Polulyakh N. V. Pronina 《Physics of the Solid State》1998,40(8):1357-1359
The effect of silicon impurities on the damping of spin-echo signals from the 57Fe nuclei of tetrahedral Fe3+ ions in epitaxial yttrium-iron-garnet films was investigated. It was found that for silicon concentrations 0.015⩽x⩽0.037 the damping of the spin echo is a two-component process, which made it possible to separate nuclei into two types,
differing by both the longitudinal and transverse magnetic relaxation times. For silicon concentrations 0.044⩽x⩽0.073 the decay of the echo can be described by one exponential and all nuclei in the sample have the same transverse relaxation
times and the same longitudinal relaxation times. The experimental results are interpreted on the basis of the supposition
that impurity “macromolecules” form around the Si4+ ions. The relaxation times of the iron nuclei in a “macromolecule” are much shorter than the relaxation times of iron nuclei
belonging to the matrix ions. The radius of a “macromolecule” is estimated on the basis of percolation theory.
Fiz. Tverd. Tela (St. Petersburg) 40, 1494–1497 (August 1998) 相似文献
17.
S. Gryś 《Opto-Electronics Review》2011,19(2):234-241
A new kind of thermal contrast, called “filtered contrast” is presented, which allows detecting and characterizing material
defects using active thermography under some assumptions on physical and thermal parameters of materials. In opposition to
known definitions of the thermal contrast, knowledge about defect-free area is not necessary and this contrast is less sensitive
to nonuniformity of heat disposal to the material surface. The measurements were performed on an experimental setup equipped
with a ThermaCAM PM 595 infrared camera and frame grabber. The step heating was chosen as heat excitation. The results demonstrate
usefulness of the 1D model of heat transfer used for determination of depth of subsurface defects. The influence of the parameter
of the smoothing filter, required for filtered contrast implementation, thermal parameters of the tested material and defect
on expanded uncertainty of determination of defect depth is also presented. Due to significant complexity of the model of
heat transfer, the conditions for the “law of propagation of uncertainty” were not fulfilled and a numerical method, i.e.,
Monte Carlo simulation is applied for the propagation of distributions. 相似文献
18.
A. V. Voitsekhovskii S. N. Nesmelov S. M. Dzyadukh V. S. Varavin S. A. Dvoretskii N. N. Mikhailov Yu. G. Sidorov 《Russian Physics Journal》2011,54(3):263-270
The effect of regions with periodic sharp 48–54 nm thick inhomogeneities in composition on the electrophysical characteristics
of MIS structures based on graded-gap n-Hg1–x
Cd
x
Te (x = 0.29–0.31) grown by molecular-beam epitaxy is studied. It is found that major electro-physical and photo-electrical
characteristics are qualitatively similar for MIS structures based on n-Hg1–x
Cd
x
Te with sharp inhomogeneities in composition (barriers) and without “barriers”. It is shown that the electrical characteristics
are mostly affected by the “barrier regions” located close to the insulator – semiconductor interface. This effect is manifested
in an increase of the effective dielectric thickness, which can be due to the fact that the regions of enhanced composition
form potential barriers for electrons, and in a decrease in the relaxation time of non-equilibrium carriers due to recombination
at the boundaries of the regions with sharp changes in composition. 相似文献
19.
H.S. Kim J.-M. Erie S.J. Pearton D.P. Norton F. Ren 《Applied Physics A: Materials Science & Processing》2008,91(2):251-254
The electrical and optical properties of ZnO thin films grown with an O2/O3 gas mixture are compared with samples grown with pure oxygen gas. The ZnO films were grown on sapphire(0001) by pulsed laser
deposition. The residual background carrier concentration is reduced by using an O2/O3 gas mixture as compared to pure molecular oxygen. In particular, a one order of magnitude reduction in residual background
carrier density (6.15×1016 cm-3) is achieved by using an O2/O3 gas mixture. The lower donor defect density is attributed to the generation of acceptor defects compensating for the residual
donor defects. Photoluminescence results show that the deep level emission increased and the band edge emission decreased
for the ZnO films grown with ozone, as compared to the samples grown with pure oxygen gas.
PACS 73.61.Ga; 78.55Et; 81.05 Dz; 81.15.Fg 相似文献
20.
We report on the first layer growth of a Mn6+-doped material. Large-size BaSO4 substrates of 10×6×4 mm3 were grown from a LiCl solvent by the flux method. Flat surfaces of undoped BaSO4 were then achieved by use of liquid-phase epitaxy (LPE) from a CsCl–KCl–NaCl solvent. Finally, BaSO4:Mn6+ layers were grown by LPE with growth velocities of approximately 3 μm h-1, at temperatures of 550–508 °C. Absorption, luminescence, luminescence-excitation and luminescence-decay measurements confirmed
the incorporation of manganese solely in its hexavalent oxidation state. This material possesses potential as a near-infrared
tunable laser with a wavelength range larger than Ti:sapphire.
Received: 7 January 2002 / Revised version: 30 March 2002 / Published online: 8 August 2002 相似文献