Related Experiment Video
Updated: Aug 13, 2026

High-resolution Thermal Micro-imaging Using Europium Chelate Luminescent Coatings
Published on: April 16, 2017
Terahertz conductivity and possible BLOCH gain in semiconductor superlattices
Y Shimada1, K Hirakawa, M Odnoblioudov
1Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
Abstract:
We have investigated terahertz emission due to dynamical electron transport in wide-miniband GaAs/Al(0.3)Ga0.7As superlattices. By noting that the time-domain THz emission spectroscopy inherently measures the step-response of the electron system to the bias electric field, the obtained THz spectra were compared with the high-frequency conductivities predicted for miniband transport. Excellent agreement between theory and experiment strongly supports that the THz gain due to Bloch oscillating electrons persists at least up to 1.7 THz. It was also found that Zener tunneling into the second miniband sets the high-frequency limit to the THz gain for the samples studied here.
Related Concept Videos
Band Theory
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
Fermi Level
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
Fermi Level Dynamics
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Energy Bands in Solids
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
Semiconductors
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
Metal-Semiconductor Junctions
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...

