Comparison Between the Electrical Properties of ZnO Nanowires Based Field Effect Transistors Fabricated by Back- and Top-Gate Approaches

Large-quality, well-crystallized growth of ZnO nanowires was done via non-catalytic thermal evaporation process on silicon substrate only by using metallic zinc powder and oxygen as source materials for zinc and oxygen, respectively. The electrical properties of the as-grown ZnO nanowires were examined by fabricating a single nanowire based FETs which were fabricated via two approaches, i.e., back- and top-gate approaches by using electron beam lithography (EBL) and photolithography processes. ZnO FETs electrical properties were characterized by I _DS–V _DS and I _DS–V _GS measurement. The fabricated single ZnO nanowire based FETs by back- and top-gate approaches exhibited field effect mobilities of ∼4.25 and ∼12.76 cm²/Vs, respectively. Moreover, the carrier concentrations for the fabricated back- and top-gate FETs were ∼1.6 × 10¹⁷ and ∼1.37 × 10¹⁸ cm⁻³, respectively. From our studies it was observed that the fabricated top-gate FETs exhibited higher and good electrical properties as compared to ZnO nanowire FETs fabricated using back-gate approaches.