A pnn double heterostructure optoelectronic switch with dual extractor electrodes was dynamically operated as an optical memory with the resulting achievement of 20 μW holding power. This value represents a reduction in holding power of about three orders of magnitude as compared to that of conventional light-emitting optical bistable devices. Complete operation, involving optical writing, regeneration, and high-speed erasing of written data through a dual extractor-electrodes configuration, was carried out with a simple driving scheme.

Very smooth and vertical etching of InP by Cl2 reactive ion beam etching has been achieved under high temperature (≈200°C), high ion energy (≈1 keV) and low Cl2 pressure (∼10-5 Torr). The roughness is estimated to be a few nm by scanning tunneling microscopy and no contamination except for Cl was observed by in situ Auger electron spectroscopy. Under these etching conditions, the etched depth is precisely controlled (σ=22 nm) by simply monitoring the electrode curtent of the ion accelerating grid. Other III-V compound semiconductors, such as GaAs, InGaAs, AlGaInP and InAlAs have also been etched smoothly and vertically. Multilayers of these materials, such as InP/InGaAsP, AlGaInP/GaInP, and InAlAs/InGaAs/InP have been etched without steps between the layers on the sidewalls.

Sidewall recombination in SiO2-capped GaAs/AlGaAs multiple quantum well mesa structures is investigated using a time-resolved photoluminescence technique. Nonradiative recombination lifetimes in annealed samples are improved significantly compared with those in samples which are not annealed. This effect contributes to a reduction in sidewall recombination velocity due to disordering of quantum wells at the sidewall by cap annealing. Numerical analysis is used to fit the experimentally observed sample size dependence of the nonradiative lifetimes to calculated curves. This shows that the effective sidewall recombination velocity is reduced from 8×106 to 4×104 cm/s.

A photoeletronic bistable device with selectable light output channels has been fabricated for implementation in photonic switching and processing systems. The device is a variation of the vertical to surface transmission electrophotonic device. Output in the stimulated light emission mode was successfully obtained from different waveguide channels by external electronic switching. Output channels could be switched at a rate of 400 Mb/s. The potential versatility of this device has been experimentally confirmed in programmable or switchable optical interconnections.

Smooth and vertical InP reactive ion beam etching has been achieved with electron cyclotron resonance Cl2 plasma at high ion energy (≥900 eV), high temperature (230°C) and relatively low Cl2 pressure (∼10-4 Torr). Smooth etching of an InP system by Cl2 plasma has often been reported as difficult compared to that of the GaAs system due to low volatility of reactive products such as InCl x . In the present work, precise control of incident ion energy and Cl2 pressure contributed to the improvement of both the vertical profile and bottom smooth surface under high substrate temperature (∼200°C). Vertical profiles were easily achieved even at high temperatures by varying the Cl2 pressure. While etching conditions suitable for vertical wall-formation were maintained, surface morphology was drastically improved by increasing ion energy above 900 eV and the bottom roughness became less than 100 nm at 1450 eV.