摘要:

The forward voltageVfacross ap+‐nsilicon diode, biased at constant current, was used to monitor the rapid annealing of damage introduced by a 5‐&mgr;sec pulse of 10 MeV electrons. Silicon diodes (1N648) were irradiated at various temperatures from 90° to over 350°K. The large increase inVfobserved immediately after the irradiation pulse recovered partially to its preirradiation value in times varying from a few milliseconds at 300°K to a few hundred milliseconds at 100°K. The ratio of the change inVfat 100 &mgr;sec after the irradiation pulse to the change after recovery had been completed varied from approximately three at 300°K to nearly seven at 100°K. The large degree of recovery indicates that defect annihilation is most likely responsible for the recovery process. The recovery kinetics of the rapid annealing are closely described by Waite's theory of diffusion‐controlled annealing involving recombination of correlated and uncorrelated defects. Particularly for temperatures above 170°K, the initial stage of recovery proceeds at a rate proportional to (t)1/2for nearly 50% of the annealing, as the theory predicts. The temperature dependence of the diffusion constant for this initial recovery is governed by an activation energy of approximately 0.12 eV. Comparison with other results indicates the possibility that diffusion of an interstitial into a divacancy, whereupon annihilation occurs, is responsible for the recovery mechanism. The low activation energy obtained is the result of the large injection of holes used in the measurements, that the injection level alters the charge state of the interstitial and recovery is enhanced.

ISSN:0021-8979    

DOI:10.1063/1.1658034

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Previous measurements of minority carrier mobility by the Haynes‐Shockley technique have ignored one or more of the effects of the three‐dimensional nature of the ambipolar diffusion, and bulk and surface recombination. In some cases, the experimental conditions were tailored so that the effects of these factors were truly negligible, imposing restrictions on the respective experimental configurations. In general, each factor does influence the drift time from which mobility estimates are made. This paper shows how their effects may be conveniently and systematically included in the data analysis and gives examples of the processing of experimental data acquired fromp‐type silicon samples of different geometries. The suitability of the new technique for measurement of mobility in thin wafers of material is pointed out.

ISSN:0021-8979    

DOI:10.1063/1.1658035

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Previously, Hall effect and other thermal activation measurements have suggested that a copper atom substituted on a gallium site in GaAs is a double acceptor with its first ionization level at 0.145 eV and its second between 0.44 and 0.49 eV above the valence band. Also, previous photoluminescence measurements have revealed broad lines attributable to copper at the Stokes‐shifted positions 0.155 eV and between 0.49 and 0.53 eV. Using an electroabsorption technique, we have studied the spectrum of substitutional copper in GaAs. We find an absorption line associated with a level at 0.463 eV above the valence band for temperatures of 103° and 300°K. We conclude from the selection rules that the wavefunction associated with this level transforms as the &Ggr;6representation of the double groupTd. Except for a weaker additional absorption line (which we do not yet understand) occurring at 0.454 eV in a singlep‐type sample, we were able to find no other lines. These results supplement earlier work on the 0.145 eV state. We propose a simple model which we feel describes the substitutional copper impurity and apply it to our measurements on the 0.463 eV state and our earlier work on the 0.145 eV state. While this model is not adequate for a first‐principles calculation, it does provide a framework in which to understand and discuss our results.

ISSN:0021-8979    

DOI:10.1063/1.1658036

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Localized vibrational modes of impurities in gallium phosphide are observed in infrared absorption. Tentative assignments for the observed absorption bands are as follows: &ohgr;L=453 cm−1is due to SiGa, 464 cm−1to NPor OP569 cm−1to11BGa, and 592 to10BGa. Other defect bands are observed at 443, 527, and 606 cm−1. However, present experimental results are not sufficient to permit identification of the impurities.

ISSN:0021-8979    

DOI:10.1063/1.1658037

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The phase diagram of the ternary system Pb&sngbnd;Sn&sngbnd;Te has been investigated by experimentally determining the liquidus surface and verifying that certain solidus compositions fall on the pseudobinary PbxSn1‐xTe line. This information is useful for growing the pseudobinary compound lead‐tin telluride from nonstoichiometric melt compositions.

ISSN:0021-8979    

DOI:10.1063/1.1658038

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

By using the vacuum evaporation method single‐crystal silicon films have been epitaxially grown on (111) spinel substrates at the substrate temperature range of 850° to 1000°C with the deposition rate of a few angstroms per second. Antimony‐dopedn‐type epitaxial films of silicon having the carrier concentration ranging from 1.3×1016to 2.1×1018cm−3were obtained by evaporating antimony during the evaporation of undoped silicon with the resistivity of 1600 &OHgr;·cm. The Hall effect and the resistivity measurements on those films were carried out over the temperature range from 77°K to room temperature. Electron Hall mobilities of films over 800 cm2/V·sec at room temperature were achieved. It was found that these film mobilities corresponded to approximately 75% of the mobilities expected on the bulk silicon with similar carrier concentrations, and that electron Hall mobilities of then‐type films with the carrier concentrations over 3×1017cm−3corresponded to about 100% of those of bulk silicon. It was also found that then‐type epitaxial films of silicon as well as thep‐type epitaxial films of silicon grown on (111) spinel substrates had higher Hall mobilities than those grown on (0001) and (1¯012) sapphire substrates with the deposition rate of a few angstroms per second by using the vacuum evaporation method.

ISSN:0021-8979    

DOI:10.1063/1.1658039

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The mobility of lithium in germanium has been determined for temperatures between 23.8° and 61.2°C by measuring the change in the capacitance with time of a reverse‐biasedp‐i‐ndiode. The mobilities of lithium thus obtained (at the specified temperatures) were 3.04×10−10cm2/V·sec (23.8°C), 5.30×10−10cm2/V·sec (36.2°C), 7.96×10−10cm2/V·sec (46.2°C), and 16.86×10−10cm2/V·sec (61.2°C). These values are higher than those that are obtained by the extrapolation of the results of others determined at higher temperatures into this temperature range. The results also suggest that a third distinct field configuration exists during the early stages of the lithium drifting in addition to the two normally considered.

ISSN:0021-8979    

DOI:10.1063/1.1658040

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The contribution of energy band deformation to the elasto‐optic coefficients of hexagonal semiconductors is calculated. It is shown that this contribution accounts for the large dispersion previously observed in certain elasto‐optic coefficients near the band edges of CdS and ZnO. The results are also shown to apply, at least qualitatively, to cubic semiconductors. The effect of the bandgap on the Pockels coefficients of hexagonal semiconductors is also treated.

ISSN:0021-8979    

DOI:10.1063/1.1658041

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Semi‐insulating, melt‐grownn‐type GaAs was irradiated with 1 MeV electrons of densities of 1016−1017electrons/cm2, thereby introducing 1017−1018cm−3defects. The irradiation decreased the dark conductivity and the photosensitivity by about an order of magnitude, indicating that additional acceptor‐like recombination centers were generated. However, no additional trapping centers were detected by thermally stimulated conductivity measurements for energies in the range 0.15–0.7 eV from either band edge. This suggests that the centers introduced had larger ionization energies than any other main trap present, namely, >0.5 eV. This is consistent with the effects of electron bombardment on luminescence in GaAs. Moreover, the calculated concentrations of the traps previously present were decreased, especially after the introduction of as many as 1018cm−3defects. This apparent decrease at these very high defect densities can be explained by assuming that the carriers tend to recombine via an intercenter process, rather than entering the bands. Annealing was found to remove most, but not all, of the effects of electron bombardment.

ISSN:0021-8979    

DOI:10.1063/1.1658042

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Solid solubilities and optical bandgaps on a large number of pseudobinary (III‐V)‐(II‐VI) systems have been studied. Four systems, GaAs&sngbnd;ZnO, GaAs&sngbnd;CdS, InP&sngbnd;ZnO, and InP&sngbnd;CdS, were found to be completely immiscible. Five systems, GaAs&sngbnd;ZnS, GaAs&sngbnd;ZnTe, InP&sngbnd;ZnS, InP&sngbnd;ZnSe, and AlSb&sngbnd;ZnTe, exhibited partial miscibility. Only three alloy systems, GaAs&sngbnd;ZnSe, GaP&sngbnd;ZnSe, and GaP&sngbnd;ZnS, were found to form solid solutions throughout the entire system. The dependence of lattice parameter on composition for the GaAs&sngbnd;ZnSe system is sublinear, while for the GaP&sngbnd;ZnSe and GaP&sngbnd;ZnS systems, it is approximately linear. The dependence on composition of optical bandgap for the first system is sublinear, and the dependence both in the second and third systems is anomalously sublinear, with the greatest changes occurring near the II‐VI end component. Preliminary analyses of optical absorption data in all the three miscible systems indicated the existence of direct bandgap material. Preliminary doping results indicated that some GaAs&sngbnd;ZnSe and GaP&sngbnd;ZnSe compositions can be doped bothn‐ andp‐type.

ISSN:0021-8979    

DOI:10.1063/1.1658043

出版商:AIP    

年代:1969

数据来源: AIP