THz radiation by quasi-ballistic electron reflection in AlSb/InAs/AlSb heterostructures

¹ Institute for Microwave Engineering and Photonics, Technical University Darmstadt - Merckstr. 25, D-64283, Darmstadt, Germany
² Faculty of Engineering, Multimedia University, Persiaran Multimedia - 63100 Cyberjaya, Selangor D.E., Malaysia

^(a) dsong@mmu.edu.my

Received: 18 October 2014
Accepted: 24 January 2015

Abstract

The new approach of generating THz signals, not by harmonic extraction, but by ballistic reflection is studied with optimized material concepts. We use an ensemble self-consistent Monte Carlo model to evaluate the generation of THz signals from ultrafast current pulses produced by quasi-ballistic electron transport and reflection in AlSb/InAs/AlSb heterostructures with a well of 200 nm length. The small electron effective mass in the -valley of InAs and the large energy separation between and satellite valleys allow electrons in InAs to propagate at a high speed at 300 K for a distance longer than 450 nm at an applied field of 20 kV/cm. The superior electron speed and the large conduction band offset of InAs/AlSb heterointerface are found to be effective to generate strong current oscillations at sub-picosecond time scales under a sinusoidal excitation.