A novel manifestation of piezoelectric effects in GaAs has been observed. The change of barrier height, φB, of Schottky diodes induced by uniaxial stresses, S, along 〈100〉, 〈011〉, 〈01̄1〉, and 〈111〉 has been measured. Shifts in φB due to the appearance of piezoelectric polarization charges at the semiconductor-metal interface for directions other than 〈100〉 are observed.

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Calculation of the Schottky barrier height at the Al/GaAs(001) heterojunction: Effect of interfacial atomic relaxations J.

The performance of an InSb infrared detector has been evaluated at liquid nitrogen and liquid helium cryogenic temperatures. A significant improvement in sensitivity was observed when the detection system was Johnson noise limited. With 300-K background radiation and diffraction limited throughout, the NEP of the detector is 1.5 x 10(-16) W Hz(-(1/2)) at 1.65 microm. Potential improvement is expected especially for astro-physical observations which are made in lower photon background conditions.

We have fabricated refractive optical elements in SU-8 resist using electron-beam lithography. Exposing an 8-μm-thick layer of SU-8 resist with a 30 kV electron beam, we demonstrate fabrication of an f/9 spherical lens, an f/2 spherical lens, and a prism with a 3° tilt. The elements all perform near the diffraction limit, with rms surface variations between 1/10 wave and 1/7 wave. The electron scattering from the thick resist is measured and shown to limit the technique to optical elements with relatively smooth surface figures.