The long-term relaxation and build-up transient of photoconductivity in Si1-xGex/Si quantum wells
Journal
Journal of Physics: Condensed Matter
Journal Volume
7
Journal Issue
23
Pages
4525-4532
Date Issued
1995
Author(s)
Abstract
The long-term relaxation and build-up transient of photoconductivity has been observed in Si1-xGex/Si quantum wells. The long-term relaxation behaviour of photoconductivity can be described by a stretched-exponential function, Ipc(t)=Ipc(0) exp(=(t/ tau )beta)(0< beta <1) for T<160 K, which is usually observed in a wide class of disordered materials. The long-term build-up transient of photoconductivity has been measured and formulated at different temperatures, which also indicates the existence of the band-tail states due to alloy disorder. The distribution of tail states has been confirmed to be exponential in energy. Our results suggest that the alloy potential fluctuations induced by compositional fluctuations can strongly influence the transport as well as optical properties of Si1-xGex/Si quantum wells.
SDGs
Type
journal article