Steuerbare Gleichrichtung in Halbleiter-Nanostrukturen - Universität ...

Abstract
In this work a voltage-tunable planar rectifier on the basis of the self switching effect (a so-
called self-switching device - SSD) was realized. The fabricated sample-structure contains
a ∼400 nm wide channel in a two dimensional electron gas (2DEG), which is defined
by etched insulating trenches. The asymmetric profile causes the self-switching effect. Its
working principle is based on a lateral pinch-off effect, which modulates the width of the
depletion zones of the narrow electron channel. Depending on the orientation of the applied
source-drain-voltage, the channel will be populated with electrons (the channel opens) or
depleted (it closes), which results in the diode-like I(V)-characteristic.
The main focus of this work was to achieve a tunability of the self-switching device by two
in-plane side gates, which modulate the width of the depletion areas in the 2DEG channel.
Therefore, the non-linear diode characteristic of the SSD can be controlled, for instance,
the on-voltage of the diode in a regime of -0,15 V up to -0,7 V, which is in contrast to a
fixed on-voltage of a conventional p-n diode.
An applied sine-wave to the source-drain contacts demonstrates a rectification of the device
up to the cut-off frequency of about 25 kHz. An on-voltage in the same range as in the dc
case is measured and the rectifier behaves almost like a half-wave rectifier. For frequencies
above 25 kHz the half-wave rectifier turns itself into a constant-current rectifier with an
offset-current, which seems to operate up to frequencies of 200 MHz.