Transitions from the ground state to excited states of the Be acceptor confined in GaAs/ Al"Ga, "As quantum wells (QW's) have been observed via two independent spectroscopic techniques: Two-hole transitions of the acceptor bound exciton (BE) observed in selective photoluminescence and resonant Raman scattering. The effect of confinement on the observed acceptor 0 transitions has been investigated by varying the QW thicknesses in the range 50 -138 A. The results obtained are compared with recent theoretical predictions. An almost linear relationship was found between the binding energy of the acceptor BE and the observed acceptor transitions. This fact implies that a correspondence to Haynes's rule in bulk should be valid also for this QW system.

MBE grown quantum devices for the detection of infrared light are introduced. These structures are based on photon-assisted resonant tunnelling and will have a projected tuning range of 5 to 30 pm, Two structures are discussed: a single quantum well device with large initial population for high absorption, and a double quantum well structure with promise of sharper detection linewidth and wider tuning range. Optical and electrical measurements of material properties are presented, and their implications on the devices discussed.

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Charge Injection Devices (CIDs) have historically played a niche role in visible imager technologies, mainly for applications requiring high radiation tolerance. They have not exhibited the radiometric performance of competing visible-imaging technologies such as CCDs, and so have not been widely applied to space instrument systems. Recent advances in CIDs have demonstrated much higher radiometric performance as well as lower noise operation, without compromising the radiation tolerance of the devices, making the devices suitable for a wide range of space instruments. We present radiometric, noise, and radiation response data for several of the newest CID designs that are candidate technologies for visible space telescope systems.

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