Thickness-dependent stress relaxation and its unreported effect on optical band gap of Al-doped ZnO thin films have been investigated. The thinnest film (∼84 nm) had a stress of -8.39× 109 Nm-2, carrier concentration of 1.73× 1019 cm-3 and optical band gap of 3.69 eV, a value significantly higher than the reported ones. With increase in thickness, magnitude of the stress decreased, and correspondingly a redshift of fundamental absorption band edge was observed. A linear dependence of optical band gap on stress in the films with a coefficient of 54.6 meV/GPa has been observed.
Bibliographical noteFunding Information:
This research was supported by the Ministry of Knowledge Economy (MKE) and Korea Institute for Advancement in Technology (KIAT) through the workforce development program in strategic technology.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)