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This paper reports on the technology and performance of piezoresistive pressure sensors that utilize GaAslAlGaAs membranes for pressure transduction into stress to induce resistance changes of p doped GaAs resistors. We have tested the sensor to differential pressure up to 8 x lo4 Pa and in a temperature range of room temperature up to 433 U.

The peculiarities of electron field emission from nanostructured GaN surface have been investigated. The current–voltage characteristics of emission current in Fowler–Nordheim plot show two parts with different slopes. There are emission current oscillations in the changing slope region. As an explanation for the experimental results a model based on the electron-emission analysis from lower (Γ) valley, upper (U) valley, and electron transition between valleys due to heating in electric field has been proposed. The electron affinities for the emission from Γ and U valleys have been determined. The decreased affinities from there valleys have been estimated for quantization in nanostructured GaN.

Theoretical analyses have been performed of the quantum-size (QS) resonance tunneling in the field-emission (FE) phenomenon for different models of the emitting structures. Such experimentally observed peculiarities have been considered as the enhancement of the FE current, the deviation from the Fowler-Nordheim law, the appearance of sharp current peaks, and a negative resistance. Different types of FE cathodes with QS structures (quantized layers, wires, or dots) have been studied experimentally. Resonance current peaks have been observed, from which the values of the energy-level splitting can be estimated.