Interesting effects of the piezoelectric and internal electric fields on the band gap of InAs/GaAs/AlGaAs:δ-Si HEMTs

¹ Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’énergie, BP 95, Hammam-Lif 2050, Tunisia
² Laboratoire de Photonique et de Nanostructures, CNRS Route de Nozay, 91460 Marcoussis, France

^a e-mail: mahmouddaoudi@ymail.com

Received: 23 July 2013
Revised: 16 January 2013
Accepted: 20 February 2014
Published online: 21 April 2014

Abstract

The quantum confined Stark effect (QCSE) has been investigated in detail in GaAs/AlGaAs and InAs/GaAs/AlGaAs HEMTs structures grown by molecular beam epitaxy on (1 0 0) oriented GaAs substrates. A power dependent photoluminescence (PL) study allowed to highlight the QCSE caused by the internal electric field in the GaAs channel then a piezoelectric field reinforce the red-shift. Increasing the Si-δ-doping leads to; first a red-shift then a blue shift at high excitation power due to the stabilize quantum well structures tendency and the saturation phenomenon. The HEMT band structures and the theoretical activated electron densities at 10 K have been studied using the finite difference method and the simultaneously solve of the Schrödinger and the Poisson equations written within the Hartree approximation.