Characterizations of Al doped zinc oxide thin films fabricated by pulsed laser deposition

At doped ZnO thin films are fabricated on the glass substrates at different temperatures by pulsed laser deposition (PLD) technique. The crystal structure, band gap energy, refractive indices, and photoluminescence are found to depend on the growth temperature. From X-ray diffraction measurements, we observe that the substrate temperature of 300-400 degreesC is the best fabrication condition for the crystallization. From the transmission, we find that the band gap energies decrease exponentially with the substrate temperature. Spectroscopic ellipsometry (SE) is used to calculate the refractive indices n of the thin films. It is found that n values of the thin films deposited at higher temperatures are in the reasonable range. However, the n values of the thin films that deposited at low temperatures deviate from the normal value. Photoluminescence measurements (PL) are also used to characterize the thin films.