A simulation of intersubband absorption in ZnO/MgxZn1-xO quantum wells with an external electric field

A detailed simulation on the intersubband absorption for 1-2,2-3, and 1-3 optical transitions in ZnO/MgxZn1-xO quantum wells is presented. The quantum-confined Stark effect induced by the internal polarization field on the absorption process is effectively controlled through an external electric field. It is easy to obtain the structural optimization of light absorption in different terahertz ranges in our numerical analysis. The absorption wavelengths corresponding to almost all of the transitions increase as the applied field varies from -500 kV/cm to 500 kV/cm. The small absorption coefficient corresponding to the 1-3 optical transition is increased by enhancing the structural asymmetry of quantum-well potential. The present work can be extended to the structural design and simulation of new optoelectronic devices based on other low-dimensional structures such as quantum wires and quantum dots. (C) 2012 Elsevier Ltd. All rights reserved.