The mechanism of alkali ion movement in glasses during electron-probe analysis must include a dependence on the temperature of the volume irradiated. Experimental results of the composition changes of binary oxide glasses of Na2O and K2O with SiO2 during electron bombardment indicate that there is a critical temperature for alkali ions in the diffusion process. Dependence of the critical temperature on composition and a comparison of these temperatures to the equilibrium temperature that can be produced from heat flow consideration indicates that for small beam diameters the actual temperature may be lower than that predicted. The rate of change of temperature may be more important to a probe operator than the equilibrium temperature.

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Observations on the use of a glow discharge mass spectrometer for the quality control of trace element levels in high-purity (99.999% or better) aluminium and aluminium alloys is presented. The procedures used, the extent of coverage of the Periodic Table, standardisation procedures and a review of the analytical results are presented and discussed. Statistical analysis of the results provides insight as to the best ways to assure consumers of these materials that their specifications are met. Other factors affecting results are also considered.

Nickel diffused into VPE n-GaAs at 700 °C for 20 min reduces the hole diffusion length Lp from 4.3 to 1.1 μm. Deep-level transient spectroscopy (DLTS) has been used to identify energy levels in Ni-diffused GaAs at Ev+0.39 eV and Ec−0.39 eV, which have identical concentration profiles. The as-grown VPE GaAs contains traces of these levels as well as an electron trap at Ec−0.75 eV in a concentration of 1.5×1015 cm−3. Ni diffusion reduces the concentration of this level by an amount that matches the increase in concentration of each of the two Ni-related levels. Previous work has shown that the Ec−0.75 eV level is related to growth under As-rich conditions, so it may be a gallium vacancy complex. A technique for measuring minority-carrier capture cross sections has been developed, and indicates that Lp in Ni-diffused VPE n-GaAs is controlled by the Ec−0.39 eV level.

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