Chen J.Z.Li C.-H.JIAN-ZHANG CHENI-CHUN CHENG2019-09-262019-09-26201200406090https://scholars.lib.ntu.edu.tw/handle/123456789/425325We report the thermal stability of room-temperature RF-sputtered Mg 0.4Zn 0.6O thin films and ZnO/Mg 0.4Zn 0.6O superlattices at 600 ¢XC and 800 ¢XC. The phase of room-temperature as-sputtered Mg 0.4Zn 0.6O is crystalline ZnO embedded in an amorphous or short-range-ordered hexagonal MgZnO matrix. Annealing at either 600 ¢XC or 800 ¢XC for 5 min transforms the matrix into a crystalline hexagonal wurtzite structure, leading to a decrease of the optical bandgap (E g) of Mg 0.4Zn 0.6O. This also results in a slight change near the absorption edge of the superlattice transmission spectrum. The films precipitate cubic MgZnO after heating Mg 0.4Zn 0.6O at 800 ¢XC for 5 min; by contrast, precipitations take at least 3 h if the samples are heated at 600 ¢XC. Heating at 800 ¢XC for more than 3 h significantly reduces the film thickness and E g, attributed to the decomposition of superlattices and diffusion of magnesium into the substrate, respectively. On the other hand, annealing the ZnO/Mg 0.4Zn 0.6O superlattice at 600 ¢XC for 12 h also produces an initial slight change in the optical transmission spectra, yet the spectra remain essentially unchanged for the remainder of the annealing process. ? 2011 Elsevier B.V. All rights reserved.AnnealingCrystal microstructureMagnesium zinc oxideMultilayersPhase transitionX-ray diffractionZinc oxidejournal article10.1016/j.tsf.2011.09.0522-s2.0-84855938529https://www2.scopus.com/inward/record.uri?eid=2-s2.0-84855938529&doi=10.1016%2fj.tsf.2011.09.052&partnerID=40&md5=7aeb3700e6a54ecc2333f666166588f7