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Be-doped ZnO thin-film transistors and circuits fabricated by spray pyrolysis in air

Research output: Contribution to Journal/MagazineJournal articlepeer-review

<mark>Journal publication date</mark>09/2013
<mark>Journal</mark>Journal of Display Technology
Issue number9
Number of pages6
Pages (from-to)688-693
Publication StatusPublished
Early online date15/11/12
<mark>Original language</mark>English


We report the fabrication of zinc oxide (ZnO) thin film transistors (TFTs) and simple integrated circuits by spray pyrolysis, and examine the role of beryllium (Be) as a dopant. Doping is achieved through addition of Be-acetylacetonate into
the parent Zn-acetate precursor solution followed by film deposition through spray pyrolysis. The microstructural properties of as-grown Be-ZnO films with different dopant concentrations are investigated using a combination of atomic
force microscopy and x-ray diffraction techniques, which show the formation of polycrystalline films. Introduction of Be is found to impact the degree of crystallinity of ZnO films where a dramatic decrease in the average grain size is observed with increasing Be concentration. To assess the effects of Be-doping on
the electrical properties of ZnO films we have fabricated Be-ZnO based TFTs using different doping concentrations. The average electron mobility calculated from these transistors is on the order of ~2 cm2V-1s-1 with the threshold voltage (VTH) exhibiting a strong dependence on Be concentration. The ability to control Vth through the introduction of Be has been exploited for the
fabrication of unipolar inverters with symmetric trip-voltages and good noise margins.