ISSN:0021-8979    

DOI:10.1063/1.1735279

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A review is given of the mechanisms of radiation damage, and of some of the resulting effects. The discussion is divided into three categories: (1) mechanisms of damage production, (2) nature and mobility of the imperfections produced, (3) effect of the imperfections on the measurement of the properties of the solid. Principal attention is given to metals, with related observations in semiconductors cited.

ISSN:0021-8979    

DOI:10.1063/1.1735280

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The average value of the kinetic energy of recoil following thermal neutron capture and subsequent gamma‐ray emission is 780 ev in silicon and 180 ev in germanium. For every neutron captured in silicon, 0.04 P31atom (therefore, 0.04 excess electron) are formed by radioactive decay. For every neutron captured in germanium, 0.098 As75, 0.012 Se77(therefore, 0.122 excess electron), and 0.304 Ga71atom (therefore, 0.304 excess hole) are ultimately formed, in this time sequence. Analysis of an experiment of J. W. Cleland on the decay of irradiatedn‐type germanium gives 0.8 electron removed from the conduction band per initially recoiling germanium atom.

ISSN:0021-8979    

DOI:10.1063/1.1735281

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The effects of irradiation on the infrared absorption and photoconductivity in silicon are reported. The absorption near the intrinsic edge is increased and drops off more gradually toward longer wavelengths. Several absorption bands are introduced by neutron irradiation with peak absorptions at 1.8, 3.3, 3.9, 5.5, and 6.0 &mgr;, respectively. The observation of each band depends upon the position of the Fermi level. The 1.8‐&mgr; band has also been studied for deuteron irradiated and electron irradiated silicon, and the 3.3‐&mgr; band has been observed in electron irradiated samples. The absorption bands arise from electronic excitations of various types of defects and associated photoconductivity has been observed for the 3.9‐&mgr; and 5.5‐&mgr; bands. In addition absorption bands have been observed at long wavelengths: 20.5, 27.0, and 30.1 &mgr;, which are associated with lattice vibration. The significance of these results is discussed.

ISSN:0021-8979    

DOI:10.1063/1.1735282

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The nature of the green and blue emission at 78°K in CdS has been investigated. On the basis of the wavelengths of absorption and emission lines the blue component is assigned as exciton decay. Measurement of the decay of the blue luminescence, following excitation by a 10−8sec pulse of 1‐Mev electrons, gave an exciton lifetime <10−8sec. Similar measurements have shown that the green component has a slower decay with emission occurring as long as 20 &mgr;sec after the excitation has ended. These results have been used to support the recombination of a free electron with a trapped hole as the mechanism for green edge emission. Heating in sulfur vapor quenches the green luminescence in a controllable fashion. From the infrared reflection spectra of CdS in the region 10 to 50 &mgr; the optical phonon frequencies were determined. The value of 305 cm−1for the longitudinal phonon is in good agreement with the prediction of Kro¨ger and Meyer from edge emission measurements, showing that the emission is coupled to the lattice through the longitudinal optical phonon. Based on an analysis of the effects on edge emission produced by heat treatment in sulfur vapor and electron irradiation with 0.20 and 1.0‐Mev electrons, a sulfur vacancy is suggested as the recombination center associated with the green edge emission.

ISSN:0021-8979    

DOI:10.1063/1.1735283

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

This paper contains a discussion of those diffusion processes commonly referred to as diffusion‐controlled reactions. Attention is focused on those aspects of the phenomena to which special care must be given in developing theoretical analyses. The discussion is documented with several experimental examples drawn from the chemical physics of semiconductors, e.g., annealing of radiation damage, ion pairing, precipitation, and the formation of complexes in solids.

ISSN:0021-8979    

DOI:10.1063/1.1735284

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The use of thermal conduction and thermoelectric measurements in studying radiation damage effects in semiconductors is discussed. The conclusion is reached that in the present state of knowledge such measurements will probably be more helpful in studying the kinetics of the formation and annealing of radiation‐introduced defects than in characterizing the structure of such defects.

ISSN:0021-8979    

DOI:10.1063/1.1735285

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

High‐purityn‐ andp‐type silicon has been irradiated lightly with Co60&ggr; rays. Analysis of the Hall mobility and magnetoresistance data indicate the introduction of levels near the conduction and valence bands. The analysis suggests the presence of triply ionized acceptors and singly ionized donors. The third ionization state of the acceptor apparently produces a level above the center of the band gap. Under more extensive irradiation a double ionization of the donors can account for the observed high resistivity. An initial increase in the magnetic field dependence of the Hall coefficient in bothn‐ andp‐type silicon may be related to the multiple ionization or to radiation annealing. The Hall mobility and transverse magnetoresistance inn‐type gallium arsenide have been studied as a function of impurity concentration and density of defects introduced by fast‐neutron irradiation. The change in the mobility and magnetoresistance with fast‐neutron bombardment suggests the introduction of levels near the band edges and of multiply ionized levels similar to those in silicon.

ISSN:0021-8979    

DOI:10.1063/1.1735286

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The theory of recombination via defects having energy levels in the forbidden gap is reviewed. Emphasis is given to those aspects which complicate interpretation of lifetime data, such as the inherent difference between steady state and transient measurements, large‐signal behavior, competing recombination mechanisms, trapping, the possible existence of strongly temperature‐dependent cross sections, and the properties of multilevel defects. A summary of the known recombination properties of bombardment‐produced defects is given.

ISSN:0021-8979    

DOI:10.1063/1.1735287

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The properties of recombination centers in germanium are obtained on the basis of lifetime data in conjunction with other information available. For recombination centers introduced by Co60gamma rays and fission neutrons, the recombination energy level position is placed at 0.20 ev below the conduction band. The room temperature hole‐capture cross sections resulting are 1.1×10−15cm2and 6×10−15cm2for Co60gammaray and fission neutron irradiation, respectively. For the case of 14‐Mev neutron irradiation the energy level is located 0.32 ev above the valence band. The room temperature hole and electron cross sections are ∼6 ×10−15cm2and 2.2×10−17cm2, respectively. The capture probabilities are assumed to be independent of temperature except for the case of gamma irradiation, for which there is apparently a fairly strong variation corresponding to a change in the activation energy of 0.07 ev. The selection of the values given above is not entirely unique. The assumptions made in their determination are discussed. The values given are directly applicable only in the case ofn‐type material, the situation inp‐type material being more complex.

ISSN:0021-8979    

DOI:10.1063/1.1735288

出版商:AIP    

年代:1959

数据来源: AIP