共查询到20条相似文献,搜索用时 13 毫秒
1.
H. Rajainmäki 《Applied Physics A: Materials Science & Processing》1987,43(3):205-208
A transient negative photoconductivity phenomenon observed in silicon doped with gold atoms by an appropriate diffusion condition has been investigated. The transient negative photoconductivity could be observed with a diode doped with gold atoms under intrinsic light-pulse illumination. In the recovery process of the transient negative photoconductivity to a steady-state dark level, two kind of time constants were observed, which may be related with the emission of electrons from gold level. A dependence of the magnitude of the peak value on the ambient temperature was observed; a qualitative explanation is given. 相似文献
2.
S. Yoshida Y. Akiba T. Kurosu M. Iida 《Applied Physics A: Materials Science & Processing》1984,35(3):145-148
A current oscillation phenomenon in SOGICON type Si device fabricated by the use of a planar process is studied. The oscillation is generated in the region between anode and notch which is located at the center on the sample. A considerably high electric field is observed in the notch region. Considering the hot-electron effect due to the high electric field, the mechanism underlying the current oscillation is discussed. 相似文献
3.
The photocurrent in n-InSb at 85K was measured as function of the applied longitudinal voltage and an additionally applied
transverse magnetic field. In the driftconfiguration the photoionized electron-hole plasma was driven into the sample volume,
and negative photocurrents resulted from the negative feedback of this motion. With the magnetic field being reversed, in
the Suhl configuration, only positive photocurrents were measured. All results are in agreement with the theory in [1]. They
were used to determine recombination coefficients in n-InSb, and, principally, the transverse diffusion coefficientD
⊥. As first observed in [13],D
⊥ proved to be anomalously enhanced above classical values if plasma instabilities were generated in the samples. 相似文献
4.
W. Schneider 《Applied Physics A: Materials Science & Processing》1976,11(2):141-146
The photocurrent in crossed fields is characterized by the feedback of the transverse ambipolar drift of the excess carriers
on the particle velocities in the longitudinal direction. In extrinsic semiconductors this reduction of the particle velocities
may cause a negative photocurrent which is here discussed for the case of low plasma densities considering the influence of
the ambipolar particle motions, the diffusion currents, the surface recombination, the bulk lifetime, the sample thickness,
and the physical magnetoresistance. Numerical calculations were performed forn-InSb at 85 K. 相似文献
5.
K. P. Ghatak A. K. Chowdhury S. Ghosh A. N. Chakravarti 《Applied Physics A: Materials Science & Processing》1980,23(3):241-244
An analytical expression of the modified form of the Einstein relation in heavily doped semiconductors in which Gaussian band
tails are formed near the lower limit of heavy doping is derived for studying the temperature dependence of the diffusivity-mobility
ratio of the carriers in such semiconductors. It is found that, with increasing temperature from relatively low values, the
ratio first increases in a nonlinear manner and then decreases till, at high temperatures, it approaches its value corresponding
to the non-degenerate condition resulting in a peak over a narrow range of temperatures. 相似文献
6.
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
7.
Clemens Schmidt 《Applied Physics A: Materials Science & Processing》1978,17(2):137-140
Silicon diffused with iron is investigated by photoconductivity and Hall-effect measurements. We used three different iron
sources, namely FeCl3, an evaporated iron film, and Fe by ion implantation. Iron exhibits inp-type, boron-doped 1 Ωcm silicon and in high-resistivity (1 kΩcm) silicon an acceptor level ofE
c
-0.55 eV. No influence of the iron was observed inn-type, phosphorous-doped 0.5 Ωcm silicon. NoE
v
+0.4 eV level was observed. It is pointed out that iron in silicon must be regarded in connection with at least three parameters,
namely the quenching rate, the chemical identity of the shallow dopant, and the initial resistivity of the silicon samples. 相似文献
8.
Yu. I. Golovin D. V. Lopatin V. V. Rodaev D. V. Konarev A. L. Litvinov R. N. Lyubovskaya 《固体物理学:研究快报》2007,1(2):R56-R58
It was revealed that the photoconductivity of layered molecular complex of fullerene C60 with saturated amine TMPDA: TMPDA · C60 is caused by intermolecular electronic processes in the fullerene layers. The intermediate magneto‐sensitive stage of photogenerating free charge carriers was found to be due to the effect of magnetic field on the rate constant of the triplet charge transfer exciton annihilation process. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
This paper is concerned with the optimization of growth conditions for a-Si1-x
Ge
x
:H alloys. It is shown that H-dilution of source gases selectively improves the band transport of electrons without significantly affecting the recombination center density or the band transport of holes. It is further shown that the beneficial effects of H-dilution are most pronounced in alloys with comparable densities of Si and Ge. 相似文献
10.
G. F. Cerofolini M. L. Polignano 《Applied Physics A: Materials Science & Processing》1990,50(3):273-286
The reproducible, mass production of almost ideal silicon p-n junctions has allowed two new phenomena to be discovered: a pure generation without recombination, and a slow capacitance-free current transient. Our present knowledge of these phenomena is reviewed and speculations about the centres responsible for them are discussed; these centres seem to be connected to ultimate, unavoidable properties of the silicon p-n junction rather than to unwanted impurities. 相似文献
11.
Carrier frequency-dependent intrinsic parameters of an ion-implanted silicon photo-MESFET have been analysed theoretically. The internal gate source capacitanceC
gs
is found to increase with increasing carrier frequency under the normally OFF condition and the change is small under the normally ON condition. Also, the internal drain-source resistanceR
ds
increases with frequency at a fixed flux density and wavelength of operation. The ion-implanted photo-MESFET could become useful as optically controlled switching device in digital circuits. 相似文献
12.
Photoconductivity and Hall voltage kinetics were measured simultaneously in SI GaAs monocrystals, using the pulsed neodimium laser excitation. The scattering and recombination centres were found to have a different influence at different time intervals of the transients (from 10 ns to some seconds). It is shown that in GaAs the photoconductivity relaxation in some time intervals can be interpreted correctly only by taking into account the mobility changes. The obtained resuls are explained in terms of recharging of the scattering centres and variations of the capture cross-section of charge carries on the local centres. 相似文献
13.
M. Kunst G. Müller R. Schmidt H. Wetzel 《Applied Physics A: Materials Science & Processing》1988,46(2):77-85
Excess charge carrier kinetics in moderately doped pSi wafers were investigated with a contactless transient photoconductivity method, i.e. the time-resolved microwave conductivity (TRMC) method. The surface structure of the wafers was changed by etching and polishing, the volume structure by irradiation with high-energy electrons. Comparison of the photoconductivity decay after excitation by strongly absorbed light and by weakly absorbed light was used to distinguish between surface and volume decay processes. The experimental results deviate from predictions based on a linear surface decay rate. These results are discussed and suggestions are made for the use of transient photoconductivity measurements to characterize semiconductor wafers. 相似文献
14.
Time-resolved photoconductivity measurements have been used to characterize electron traps in wide-gap n-HgO0.3Cd0.7Te for the first time. The characterization was made possible by combining the time-resolved photoconductive data with the analytical method conventionally used in DLTS spectroscopy. Two electron traps were found in the band gap with 61 meV and 79 meV below the conduction band edge, their concentrations are 1.1×1013 cm–3 and 5.8×1011 cm–3, respectively. Compared with DLTS spectroscopy, this characterization method markedly simplifies sample preparation and experimental procedure. 相似文献
15.
T. Volk M. Wöhlecke N. Rubinina N. V. Razumovski F. Jermann C. Fischer R. Böwer 《Applied Physics A: Materials Science & Processing》1995,60(2):217-225
We report on a detailed investigation (EPR, SHG, optical absorption, luminescence and Raman scattering) on the new damage-resistant impurity indium in LiNbO3, where the increased photoconductivity strongly reduces the photorefractive effect. EPR and optical absorption measurements point to a complete disappearance of the Nb antisite in LiNbO3: In for all In concentrations. We believe that the very effective driving out of Nb antisites by In is due to the trivalent charge state of In and the possibility of charge self-compensation. Similarities in the properties of Mg-, Zn- or Indoped samples are discussed. Simultaneous doping with In and Zn leads to an addition of both contributions, in particular for optical frequency doubling and luminescence. Raman studies prove that In does not improve the stoichiometry of the crystals. Indium doping provides the possibility to control simultaneously phase-matching conditions and to reduce drastically photorefraction. Therefore, In co-doped LiNbO3 compositions are promising materials for applications after solving contemporary growth problems. 相似文献
16.
The diffusion of Au in Si is known to take place via the interchange of Au atoms between substitutional (Au
s
) and interstitial (Au
i
) sites. So far it has generally been believed that this interchange involves lattice vacancies (V) and that it occurs via
the Frank-Turnbull mechanism V+Au
i
⇆Au
s
. It is stated in the literature that this model explains the observation that the Au
s
concentrationC
s
m
in the centre of Au-diffused Si wafers increases with timet according to
. We show that this statement is incorrect, i.e., the Frank-Turnbull model cannot account for the
law. Such a dependence is expected in the case of Si wafers with a sufficiently low density of internal sinks for self-interstitials
if the Au
i
−Au
s
interchange is controlled by the so-called kick-out mechanism Au
i
⇆Au
s
+1. Since this mechanism involves self-interstitials (I) the present result is in accordance with the fact that under high-temperature
equilibrium conditions the dominating intrinsic point defects in Si are self-interstitials and not vacancies as in Ge or metals. 相似文献
17.
R. G. van Welzenis 《Applied Physics A: Materials Science & Processing》1981,26(3):157-163
The thresholds in energy for 5 different impact ionisation processes in InSb at 77K were calculated on the basis of a critical review of the available bandstructure data for largerk values. An accurate threshold value of 243 meV ± a few meV is given for the main process. It is shown that production of light holes by impact ionisation is highly improbable. It is suggested that double ionisation and light hole initiated ionisation may be equally important in interpreting quantum efficiency data. Impact ionisation by L-band electrons may contribute significantly to the avalanche in Gunn domains, explaining the rapid quenching of the latter. 相似文献
18.
Study of transient photoconductivity of GaN epilayer grown by metalorganic chemical vapor deposition 总被引:1,自引:0,他引:1
Z.Z. Chen B. Shen X.Y. Zhang R. Zhang P. Chen Y.G. Zhou L. Zang R.L. Jiang Z.C. Huang Y.D. Zheng Z.S. Wu X.T. Sun F. Chen 《Applied Physics A: Materials Science & Processing》1998,67(5):567-570
Received: 24 March 1998/Accepted: 10 July 1998 相似文献
19.
The instability of the electron-hole plasma produced by continuous photoexcitation in short semiconductor structures is investigated theoretically. The applied electric field is considerably disturbed by photogenerated charge carriers. At a sufficiently intensive photogeneration plasma instability occurs. The frequency of current oscillations due to the instability, as shown by numerical simulation for a GaAs structure, is in the range of 1011–1012s–1. 相似文献
20.
Ch. M. Hardalov K. D. Stefanov D. Sueva 《Applied Physics A: Materials Science & Processing》1995,61(2):107-109
Deep-Level Transient Spectroscopy (DLTS) measurements were carried out on silicon p+nn+ diodes before and after irradiation with fast neutrons at room temperature with fluences 5.5×1011 and 1.0×1012 n/cm2. It was found out, that all preexisting defects decreased their amplitudes during irradiation, while only one defect, identified as a single-charged divacancy, increased in amplitude. An interpretation is proposed in terms of the cluster model, and the applicability of the DLTS is discussed. 相似文献