Mobility-Modulation Field Effect Transistor Based on Electrospun Aluminum Doped Zinc Oxide Nanowires

Abstract

This paper presents the findings of research into field effect transistors (FET) based on aluminum doped zinc oxide (AZO) nanowires that resulted in developing an effective field-effect channal conductivity control method implemented by intensive modulation of charge carriers mobility. AZO (Al ∼ 2% at.) nanowires were fabricated by electrospinning technique, and the obtained nanocrystalline nanowires had diameter of 150 – 200 nm and average grain size of ∼10 nm. FET was assembled using AZO nanowires with back side gate configuration and demonstrated n-type behavior and on-off current ratio up to 103. Using grain boundary (GB) model we have found electron concentration in the FET channel in off-state and on-state to be 1.8·1019 cm−3 and 4.1·1019 cm−3, respectively. Meanwhile, the corresponding effective field-effect mobility changed significantly from 2.5·10−6 cm2/V·s to 3.3·10−3 cm2/V·s. Mobility change (∼103) was attributed to lowering of potential barrier inside GB. Areal trap concentration was estimated as 3·1013 cm−2 and donor concentration as 4.5·1019 cm−3. The results presented open up new opportunities for the developing of a new type of mobility-modulation field-effect transistors.