E-beam evaporated ZnO thin films: Fabrication and characterization as UV detector
Istituto Nazionale di ricerca Metrologica INRIM, Strada delle Cacce 91, 10135, Torino, Italy
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Revised: 30 January 2015
Accepted: 1 February 2015
Published online: 12 March 2015
In the present paper, fabrication and structural, optical and electrical characterization of ZnO thin films grown by electron gun technique are reported and the performances of a prototype of UV photodetector based on them are illustrated. ZnO thin films, fabricated on sapphire by e-beam evaporation followed by a two-step ex situ treatment (annealing and oxidation), are polycrystalline, with a smooth surface and show very good visible transparency and an energy gap of 3.2eV. Preliminary results on fabrication and characterization of an UV detector are reported. The Al interdigitated contacts show a Schottky behavior, which is strongly desired in view of applications since it has many advantages in the aspects of high quantum efficiency, response time, low dark current, high UV/visible contrast and possible zero-bias operation.
© Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg, 2015