Terahertz (THz) spectroscopy is an important tool to study properties of semiconductors to gain important insight into materials. Generating THz radiation as freely propagating beam made THz Spectroscopy an ideal tool for investigating various behaviors. Effect of THz-Time Domain Spectroscopic (THz-TDS) irradiation, applied to a potential well structure, is considered here based upon an experimentally verified model. At ambient temperature, there will be two mechanisms of scattering alongside others: charge-charge scattering and electron-phonon scattering as proposed by Hendry et al. GaAs-Al_xGa_1-xAs double barrier heterostructure was selected. Mole fractions were chosen for which appropriate Γ-band conduction energy differences were considered. Only optical phonon interactions were considered. Effects of these mechanisms have been demonstrated in terms of broadening of transmission probabilities, group velocity, phase coherence, quantum well transit time and most importantly, charge density against various pump fluences. To get full impact of THz-TDS for charge density, modified Fermi distribution was considered and significant results were obtained. An experimental setting emitting electron at different injection energy can be employed to enumerate broadening in terms of plasma frequency and thus, pump fluence. Also, the impact of different elemental compositions in the AlGaAs/GaAs or other resonant tunneling structures may be very precisely determined.

Date Published: 10 September 2010
PDF: 11 pages
Proc. SPIE 7755, Nanophotonic Materials VII, 77550J (10 September 2010);

Published in SPIE Proceedings Vol. 7755:
Nanophotonic Materials VII
Stefano Cabrini; Taleb Mokari, Editor(s)