Acousto-electric deep-level transient spectroscopy in semiconductors

Radiative recombination during ambipolar carrier transport by surface acoustic waves in GaAs quantum wells

“…After that, they should remain charged for times considerably larger than the SAW period T SAW . 7 The second type of defects are charged sites in the barriers separated from the GaAs QW plane by a distance d much larger than the exciton Bohr radius (a B ), but considerably shorter than the SAW wavelength. Under these conditions, the electric potential d generated by the defect in the QW plane will exert only a small force on excitons ͓proportional to ٌ(ٌ d .p), where p denotes the exciton dipole moment͔, but will strongly affect the SAW-induced transport of positive and negative charges, which are separated from each other by a distance SAW /2ӷa B .…”

“…An important issue associated with the SAW-induced transport concerns the role of defects, which may distort the charge packets and reduce the transport efficiency. 6,7 In this work, we investigate the effect of defects on the SAWinduced ambipolar transport of e and h in GaAs quantum wells ͑QWs͒ using spatially resolved photoluminescence ͑PL͒. We demonstrate that the transport efficiency is limited by the radiative carrier recombination at sites located along the SAW propagation path.…”

Acoustic Spectroscopy of Nanostructures in Condensed Matter

“…The surface acoustic wave (SAW) technique uses a nonlinear AE interaction between the SAW electric field and free carriers in an interface region which generates a transverse AE signal (TAS) across the structure [4]. The longitudinal acoustic wave (LAW) technique uses an acoustoelectric response signal observed at the interface of the semiconductor structure when a longitudinal acoustic wave propagates through the structure [5,6].…”

Acousto-electric study of interface trapping defects in GaAs epitaxial structures

“…Up to now no appropriate experimental methods exist to characterize these interface defects. Recently some publications reported the transient acoustoelectric effect in semiconductors with defects [4][5][6]. Transient transverse acoustoelectric voltage (TAV) generated in semiconductors has already been used in the past [7,8], but this using hasn't be aimed to interface defect characterization and hasn't include corresponding acousto-optical measurements.…”