Semiconductors group

Abstract:

The trapped charge density at the polymer-insulator boundary of polymer transistors was monitored by terahertz time-domain spectroscopy. Additionally, the thermal removal of trapped holes and the light-induced transmission change were studied. © 2006 Optical Society of America.

Abstract:

Terahertz photonics is a rapidly growing field. The ultra-fast dynamics of charge carriers in semiconductors is closely linked to the performance of THz photonic devices. We study a range of ion-implanted and nano-scale semiconductors for application in novel terahertz devices.

Abstract:

We have investigated the conductivity of equilibrium and photoexcited electrons in nanoporous Indium phosphide (InP) of various porosities and of two orientations: (100) and (111). We observed an enhanced transmission through the nanoporous samples compared with bulk InP, resulting from a suppression of the conductivity by the pores. The frequency-dependent conductivity was extracted numerically from the transmission data. We examined the dynamical conductivity of photoexcited carriers using optical-pump THz-probe spectroscopy. After the rapid photoexcitation of electrons, the time-resolved conductivity was observed to decay slowly, with carrier recombination lifetimes exceeding 1ns for all (100)- and (111)-oriented samples.