Peter H. Beton

TL;DR: In this article, an AlGaAs/GaAs heterojunction bipolar transistor with a double-barrier resonant-tunnelling structure (DBRTS) inserted between the base and the collector has been investigated.

TL;DR: In this article, the width of the QHE plateaus ΔB was investigated in GaAs/AlGaAs using DC and microwave (MW) techniques and it was shown that ΔB is narrower at MW frequencies than at DC and saturates below 2.4K.

Abstract: The electro- and photoluminescence of p-i-n and n-i-n GaAs double-barrier resonant tunnelling diodes have been investigated for various concentrations of free carriers (either holes or electrons) in the quantum well (QW). For these structure it is possible to change the relative electron or hole density quasi-continuously with applied bias voltage. At electron densities well below that for exciton unbinding, the formation of negatively charged excitons (X - ) is demonstrated. In asymmetric QW structures the electron densities can be increased above the critical density and exciton unbinding is observed in the luminescence spectra. We also report the observation of the positively charged exciton (X 2 + ) in the luminescence spectra of a GaAs quantum well. The conditions for forming X 2 + are compared with those needed to see the negatively charged exciton (X - ), the heavy-hole free exciton (X) and free carrier recombination.

TL;DR: In this paper, the mesoscopic effects in small-area resonant tunneling devices, which are inherently non-linear conductors, exhibiting strong deviations from Ohm's Law behavior, are discussed.

TL;DR: In this paper, the authors present the first observations of rectification fluctuations in a mesoscopic conductor; a small n+-GaAs wire, which enables them to examine directly that part of the conductance fluctuation that is antisymmetric in the applied voltage.