The vapor above the SrO–Pt system was bombarded with electrons and the ion fragments analyzed by a mass spectrometer. Evaporator temperatures ranged from 1600°K to 1800°K. Log Sr+ vs 1/T plots were found to be time dependent initially. Eventually the plots became stable, and could be represented by two straight lines having a slope of 60 kcal/mole at the higher temperatures and of 138 kcal/mole at the lower temperatures. The appearance potential for Sr+ was approximately 5 volts. The ratio of Sr+ to SrO+ was between 10 and 100. These results indicate that thermal dissociation of SrO took place. An explanation based on a diffusion-limited mechanism is offered for the smaller slope of the upper part of the log Sr+ vs 1/T plot. The behavior of the SrO–Pt system is compared with that of the BaO–Pt system. The latter system does not appear to exhibit thermal dissociation.
The level scheme for A c =^0 is shown in Fig. 11 (b). In order to find e F one has to solve the Fermi level equation (A8) using the effective donor-state energy (A9) in which E d (l) is given by (A7). This leads to a complicated expression for e F which can be solved numerically when the quantities A c and E 2 are known.One can find, however, a simple expression for the limiting case 4:A c /kT^>l. This condition will always be satisfied at low enough temperatures. The influence of the upper three states of the donor multiplet can then be neglected. At low enough temperatures, i.e., when the total electron concentration n<^Nd-N a and n<^N ai the Fermi energy shifts parallel to the donor ground state energy when stress is applied so that €^=2A c -(4A c 2 +6 2 )l (A15) Substituting (A15) into (A6) yields the final result for the respective conductivity changes:T HE rate at which carriers are removed from the conduction band in InSb by electron bombardment has been measured as a function of energy in an effort to determine the threshold electron energy for the production of atomic displacements. The results are shown in Fig. 1. The irradiation and electrical conductivity measurements, from which the carrier removal rates, dn/dN e , were derived, were carried out at liquid nitrogen temperature. The sample was ;^-type with 1.4X10 14 carriers/cm e and a mobility of 3.5X10 5 cm 2 /volt sec at liquid nitrogen temperature. The sample thickness was 0.017 cm. Figure 1 may be separated into an energy region in which dn/dNe changes rapidly with energy and a "tail" region in which dn/dN e changes very slowly with energy, suggesting that two different processes may be responsible for the observed conductivity changes. This possibility was investigated by studying the isochronal recovery of damage produced at different electron energies. Figure 2 shows the data for samples annealed after bombardment at 240 kev and 400 kev. The 240-kev damage recovers in two stages labeled I and II f This research was supported by the Aeronautical Research laboratory, Wright Air Development Center, ACT f K-l 1 -= =fc sinh(e/&r)+cosh(€/&r) cro L 2K+1 J Xexp{[2A c -(4A c 2 +e 2 )*]/&r} -1, (A16)with € given by (A5). The plus sign applies to arrangement C, the minus sign to arrangement D.The case of finite A c differs from the case A c =0 considered previously in that the total carrier concentration in the conduction band is changed by the stress. This change in n is reflected in a change of the Hall coefficient R:In deriving this result, the condition 4:A c^> kT was assumed to hold and the effect of stress on the ratio of Hall mobility to drift mobility was neglected.in the diagram. The 400-kev damage recovers entirely in Stage II and the annealing of a sample irradiated at 700 kev shows nearly all the recovery occurring in Stage II (with the rest of the recovery occurring at higher temperatures). The absence of recovery in Stage I after irradiation at these energies may be due to heating of the sample during the irradiation. The conductivity chang...
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