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100‐keV e‐beam lithography and electroplating of gold have been used to fabricate a device for the measurement of quantum changes in magnetic flux. The structure is defined in a 200‐nm‐thick layer of a copolymer of methyl methacrylate and methacrylic acid (PMMA/MAA) on top of a Si wafer covered by 150 nm of Si3N4. The device is a square frame of 2×2 μm2 and 100‐nm linewidth. Gold was electroplated to a thickness of 100 nm. This technique allows the fabrication of high resolution, high aspect ratio gold structures.

The generation of 15‐ps light pulses at 1.23 and 1.26 μm having 200 mW peak power at a repetition rate of up to 10 MHz from directly modulated unbiased V‐groove InxGa1−xAsyP1−y lasers is reported. Specially designed avalanche generators are employed for modulation of the laser injection current. The light pulses are analyzed using microstructured Ge photodetectors having a response of 62 ps at full width half‐maximum. A deconvolution technique based on a theoretical analysis of the complete circuit of the detection system is applied to reduce the large error occurring normally when the characteristics of fast pulses are determined from the response of much slower detectors. This technique is proved by independent experiments to hold. A spontaneous lifetime of 1.5 ns of the charge carriers in the active layer of the laser is determined from the measured delay times between the optical and electrical pulses.

We report the generation of short light pulses of 23‐ps duration from an unbiased proton implanted double heterostructure cw laser by direct gain modulation. Repetition frequencies up to 10 MHz and a typical peak power of 300 mW are achieved. The time behavior of the light output is largely independent of the rise and fall time of the modulation current, since the first relaxation oscillation of the laser is utilized.

It is shown that strained isoelectronically doped buffer layers grown on GaAs and InP wafers allow one to reduce the dislocation density drastically by a factor greater than 20. Correspondingly, the photoluminescence efficiency of near‐band‐edge emission is enhanced by about the same factor. By deep level transient spectroscopy measurements practically no deep levels can be detected in contrast to uncoated wafers. Applied to device fabrication a great improvement is found in comparison to conventionally fabricated optoelectronic and electronic devices.

The electrical characteristics of Schottky diodes fabricated on silicon surfaces subject to low‐energy (10 keV) argon ion implantation have been studied as a function of Ar+ ion dose. Significant changes in electrical characteristics are seen for ion doses as low as 5×1011 cm−2, well below the amorphization threshold dose for Si. In conjunction with the ion energy threshold established earlier for Si surface damage effects (∼25 eV), these results outline fundamental limits on the effect of ion‐assisted dry etching processes on Si surface barriers.