共查询到20条相似文献,搜索用时 296 毫秒
1.
2.
3.
4.
5.
6.
7.
分别采用二种不同方法测量分子束外延(MBE)生长GaAs/In0.2Ga0.8As单量子阱结构的导带不连续量ΔEc:1) 考虑样品界面电荷修正的电容-电压(C-V)分布;2) 量子阱载流子热发射产生的电容瞬态(DLTS).C-V测得的ΔEc=0.227eV,大约相当于89% ΔEg.DLTS测得的ΔEc=0.229eV,大约相当于89.9% ΔEg.结果
关键词: 相似文献
8.
用最小偏向角法在20℃下精确测量了0.62Pb(Mg1/3Nb2/3)O3< /sub>-0.38PbTiO3( 0.62PMN-0.38PT)单晶的折射率,给出了该温度下折射率色散的Sellmeier方程.研究了能带 结构与折射率的关系,计算了样品的Sellmeier光学系数:对no,E0=5.50eV,λ0=0.2 26μm,S0=1.004×1014m-2,Ed=28.1 0eV;对ne,E0=5.57eV,λ 0=0.223μm,S0=1.017×1014m-2,Ed=28.10eV.A BO3型钙钛矿材料中,BO6八面体基元决定了晶体的能带结构,对折 射率产生重要影响.
关键词:
PMNT单晶
折射率
Sellmeier光学系数 相似文献
9.
运用第一性原理杂化泛函研究了本征缺陷(O空位和Ga空位)对于β-Ga2O3的几何结构和电子性质的影响.计算结构表明:杂化泛函B3LPY能很好的描述β-Ga2O3的几何结构和电子结构,能与实验符合.含O缺陷的形成能在富氧和贫氧下分别为4.04和0.92 eV,优于含Ga缺陷的体系.空位缺陷的出现对于理想Ga2O3的晶格参数影响不显著,只是在O空位体系中,空位附近Ga-O键长有0.1?变化.含空位缺陷的体系的禁带中都有缺陷能级的出现,含Ga和O空位缺陷的Ga2O3的光跃迁能分别为1.93 eV(β自旋)和2.92 eV,有很明显的光吸收的拓展,从理论上解释了Ga2O3作为光催化材料的潜在应用. 相似文献
10.
本文用固相反应烧结制备出Li2Mo2O6多晶材料。经X射线分析、红外光谱和电子顺磁共振谱(EPR)的研究,确定了它的结构是Li2Mo2O4和MoO2两个晶相组成的烧结体。钼离子以四价状态存在于MoO2晶相结构中。采用交流阻抗谱分析了晶界与温度变化的相关性。测得了样品的ln(σ总T)-1/T 曲线是由两段直线和一段曲线所组成;总电导率化能σ27℃=1.36×10-3(Ω·cm)-1,σ115℃=1.49×10-3(Ω·cm)-1,σ300℃=9.71×10-3(Ω·cm)-1,σ370℃=2.42×10-3(Ω·cm)-1;电导活化能E1=0.043eV,E2=0.235eV,E平均=0.76eV。采用维格纳极化电池法测得电子电导率σe,σe27℃=2.240×10-5(Ω·cm)-1,σe300℃=4.476×10-3(Ω·cm)-1。实验证明,室温下材料为固体电解质,300℃附近为良好的离子与电子混合导体。
关键词: 相似文献
11.
D.C. Schmidt J.F. Barbot C. Blanchard P. Desgardin E. Ntsoenzok G. Blondiaux 《Applied Physics A: Materials Science & Processing》1997,65(4-5):403-406
9 to 1013 particles/cm2 have been investigated by the deep level transient spectroscopy technique and capacitance-voltage profiling. Under low fluence
irradiation at least four main electron traps have been observed. With further increase in irradiation fluence, two new levels
located at Ec-0.56 eV and Ec-0.64 eV appear on the high-temperature side of the DLTS signal. The slope change observed in the amplitude variations of
the singly negative charge state of the divacancy versus the dose takes place when these two new levels appear. This suggests
that both are multivacancy-related defects. After annealing at 350 °C for 15 min, all electron traps have disappeared. Moreover,
no shallow levels are created during the annealing.
Received: 12 December 1996/Accepted: 6 May 1997 相似文献
12.
D. Walz J. -P. My G. Kamarinos 《Applied Physics A: Materials Science & Processing》1996,62(4):345-353
The recombination lifetime and diffusion length of intentionally iron-contaminated samples were measured by the Surface Photo Voltage (SPV) and the Elymat technique. The lifetime results from these techniques for intentionally iron-contaminated samples were analysed, in particular for the aspect of the injection-level dependency of recombination lifetime. Based on theoretical considerations, a method for the analysis of deep-level parameters combining constant photon flux SPV and Elymat measurements has been developed. This method is based on a detailed numerical analysis of the Elymat technique, including the Dember electric field, the characteristics of the laser beam, the transport parameters of the semiconductor and multilevel Shockley-Read-Hall (SRH) recombination kinetics. The results of the numerical simulation are applied to the analysis of recombination lifetime measurements on intentionally iron-contaminated samples. We compared numerical simulations and experimental results from SPV and Elymat for p-type samples using the classical acceptor level atE
v +0.1 eV and the donor level of FeB pairs atE
c -0.3 eV as recombination centre. Better consistency in the interpretation of the results has been found in the doping range 1014–1016 cm–3 supposing theE
c -0.3 eV level as predominant recombination centre. An attempt to extract the electron and hole capture cross-sections for this defect is made. 相似文献
13.
Abstract The nature of the irradiation induced defects in germanium single crystal doped with tellurium was studied by DLTS and electrical measurements. The Ec-0.21 eV level produced by irradiation with 1.5 MeV electrons was studied by DLTS technique. It was found that the defect associated with the Ec-0.21 eV level is divacancy. The E-center like defect (group V impurity-vacancy pair) introduces the Ec-0.20 eV level in samples doped with group V impurity. The level introduced by tellurium (group VI impurity)-vacancy pair is located at deeper than Ec-0.21 eV. The Ec-0.16 eV level was generated by the annealing at 430 K. A model for the defect associated with the level is proposed to be a tellurium-vacancies complex. 相似文献
14.
Deep-level transient spectroscopy (D.L.T.S.) has been applied to the determination of defects in ion implanted silicon. Preliminary
results concerning defects introduced by 130 KeV phosphorous ion implantation are described. Four electron traps are found:
atE
c
-0.21 eV,E
c
-0.39 eV,E
c
-0.52 eV andE
c
-0.58 eV and their cross-sections estimated. The annealing behaviour in the range 450–800°C of these traps is described.
Work supported in part by the Institute of Physics, Polish Academy of Science, Warsaw.
Laboratoire associé au C.N.R.S. 相似文献
15.
F.D. Auret P.J. Janse van Rensburg W.E. Meyer S.M.M. Coelho Vl. Kolkovsky J.R. Botha C. Nyamhere A. Venter 《Physica B: Condensed Matter》2012,407(10):1497-1500
The electronic properties of defects introduced by low energy inductively coupled Ar plasma etching of n-type (Si doped) GaAs were investigated by deep level transient spectroscopy (DLTS) and Laplace DLTS. Several prominent electron traps (Ec—0.046 eV, Ec—0.186 eV, Ec—0.314 eV. Ec—0.528 eV and Ec—0.605 eV) were detected. The metastable defect Ec—0.046 eV having a trap signature similar to E1 is observed for the first time. Ec—0.314 eV and Ec—0.605 eV are metastable and appear to be similar to the M3 and M4 defects present in dc H-plasma exposed GaAs. 相似文献
16.
17.
Deep level transient spectroscopy (DLTS) and Laplace-DLTS (L-DLTS) have been used to investigate defects in an n-type GaAs before and after exposure to a dc hydrogen plasma (hydrogenation). DLTS revealed the presence of three prominent electron traps in the material in the temperature range 20-300 K. However, L-DLTS with its higher resolution enabled the splitting of two narrowly spaced emission rates. Consequently four electron traps at, EC—0.33 eV, EC—0.36 eV, EC—0.38 eV and EC—0.56 eV were observed in the control sample. Following hydrogenation, all these traps were passivated with a new complex (presumably the M3), emerging at EC—0.58 eV. Isochronal annealing of the passivated material between 50 and 300 °C, revealed the emergence of a secondary defect, not previously observed, at EC—0.37 eV. Finally, the effect of hydrogen passivation is completely reversed upon annealing at 300 °C, as all the defects originally observed in the reference sample were recovered. 相似文献
18.
H. Lefèvre 《Applied Physics A: Materials Science & Processing》1982,29(2):105-111
The annealing behavior of trap-centers was studied in float-zone silicon wafers containing A-swirl defects. Samples from areas of high and low A-swirl density were annealed in nitrogen ambient between 100° and 900 °C, and analysed using the Deep Level Transient Spectroscopy. The results indicate, that two levels atE
c
}-0.07 eV,
n=4.6×10–16 cm2, andE
c–0.49eV,
n=6.6×10–16cm2 are caused by one defect, for which the silicon di-selfinterstitial is a likely interpretation. A level atE
c
}-0.11 eV was assigned to interstitial carbon. Both defects annealed out at about 170 °C. After 600 °C annealing an additional level atE
c–0.2 eV was detected, which was attributed to an interstitial silicon carbon complex. Heat treatment at 800 °C generated a new level atE
c–0.49 eV,
n=2.9×10–16cm2 only in the area of high A-swirl defect density. This level was also observed after oxidation and subsequent annealing of silicon. 相似文献
19.
R. Czaputa 《Applied Physics A: Materials Science & Processing》1989,49(4):431-436
Recent investigations on transition-metal impurities in silicon emphasizing the effect of the combined diffusion of two transition metals are presented and briefly discussed. The electronic properties and basic thermal kinetics are analysed by DLTS. The conversion of a Pd-related multivalent defect atE
c-0.35 eV andE
c-0.57 eV to the Pd-related defect atE
c –0.22 eV is observed, and a Pd-Fe complex level atE
c –0.32 eV is identified. The annealing characteristics of the multivalent Rh levels atE
c-0.33 eV andE
c-0.57 eV are observed, and used to analyse the influence of prior Rh doping on the Au diffusion. A complex formed by the codiffusion of Au and Cu is observed atE
v+0.32eV andE
v+0.42 eV, and shown to exhibit bistable behavior as does a similarly produced Au-Ni complex observed atE
v + 0.35 eV andE
v+0.48 eV. 相似文献
20.
Abstract Hydrostatic pressure has been used as a variable to investigate the Ec-0.164 eV acceptor level for the oxygen-vacancy (O—V) defect in γ-ray irradiated Si, and the annealing/formation of oxygen-related defects in neutron-irradiated Si. The acceptor level is found by deep level transient spectroscopy to move closer to the conduction band and away from the valence band at rates of 3.9 meV/kbar and 2.4 meV/kbar, respectively, i.e., the level moves higher in the gap. There is also a relatively large inward (outward) breathing mode lattice relaxation (4.6±1.2 Å3/electron) accompanying electron emission (capture) from this level. Both results reflect the antibonding nature of the level and are qualitatively consistent with the Watkins—Corbett model for the O—V defect. The annealing rate was found by infrared absorption to increase with pressure for the O—V defect at 350°C with a derived activation volume of ?4.5 Å3/defect, where the negative sign implies inward relaxation (contraction) on annealing. Pressure has relatively little effect on annealing of the C—Si—O C(3) defect which is interstitial in nature, but strongly favors the formation of the dioxygen (2 oxygen atoms per vacancy, i.e., O2—V) defect. The intensity of the O2—V band after annealing at 20 kbar is 5 times higher than that following similar annealing at 0 kbar. Additionally, this intensity at 20 kbar is higher than that achievable by any isochronal or isothermal annealing steps at 0 kbar. These annealing/formation results are discussed qualitatively in terms of models for the various defects. 相似文献