Structural, optical and electronic structure studies of Al doped ZnO thin films

• Al doping increases grain size due to relaxation in compressive stress.
• Band gap also increases, due to the Brustein–Moss shift.
• Electronic structure is modified with Al doping.
• Surfaces of undoped and doped thin films are smooth, densed and crack free.

Structural, optical and electronic structure of Al doped ZnO thin films grown using pulsed laser deposition on glass substrate are investigated. X-ray diffraction measurements reveal that all the films are textured along the c-axis and have wurtzite structure. Al doping in ZnO films leads to increase in grain size due to relaxation in compressive stress. Enhancement in band gap of ZnO films with the Al doping is also noticed which can be ascribed to the Brustein–Moss shift. The changes in the electronic structure caused by Al in the doped thin film samples are understood through X-ray absorption measurements.