On the anomaly in the electrical characteristics of thin film transistors with multi-layered sol-gel processed ZnO

Vahid Mirkhani, Kosala Yapabandara, Shiqiang Wang, Min Prasad Khanal, Sunil Uprety, Muhammad Shehzad Sultan, Burcu Ozden, Ayayi Claude Ahyi, Michael C. Hamilton, Mobbassar Hassan Sk, Minseo Park

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

A set of bottom-gate Zinc Oxide (ZnO) thin film transistors (TFTs) with active layers containing 1, 4 and 8 layers of spin-coated ZnO were fabricated and their electrical characteristics such as transistor transfer and capacitance-voltage characteristics were analyzed. The transconductance of the single-layered ZnO transistor shows a single peak. On the other hand, multiple peaks and humps were observed in the transconductance and capacitance-voltage characteristics of multi-layered ZnO transistors. The multi-layers were grown by reiteration of the spin-coating process, producing ZnO − ZnO interlayer-interfaces. The surface of the ZnO layer in contact with the ambient contains active sites, resulting in chemisorption of ambient gases such as oxygen prior to the deposition of subsequent layers. The chemisorbed species become negatively-charged and form charge sheets, depleting the surface/interface region. It was proposed that the formation of depletion layers at ZnO − ZnO interlayer-interfaces is the main cause for the observed anomaly.

Original languageEnglish (US)
Pages (from-to)152-156
Number of pages5
JournalThin Solid Films
Volume672
DOIs
StatePublished - Feb 28 2019

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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