Chemical surface passivation of HfO₂films in a ZnO nanowire transistor

Abstract

The effects of different annealing atmospheres on the chemical surface structure of HfO2 gate dielectric layers have been evaluated in terms of the improvement in the transconductance (gm), current on/off ratio (Ion/Ioff), and carrier mobility (μe) of a back-gated ZnO nanowire field-effect transistor (FET). Compared to O2 and N2 annealed HfO2-gated transistors, the H2 annealed HfO2-gated ZnO nanowire FET exhibited a higher transconductance of 1.77 × 10−7 A V−1, on/off current ratio of ∼1.2 × 104, and electron mobility of 11.90 cm2 V−1 s−1.

High performance ZnO nanowire field effect transistors with organic gate nanodielectrics: effects of metal contacts and ozone treatment

“…Using the measured g m ( figure 3(d)) and equations (1), (2), an μ eff can be estimated for the NW-FETs. For ozone-treated single ZnO NW-FETs, the calculated μ eff is ∼1175 cm 2 V −1 s −1 , which is larger than typically reported values for ZnO NW-FETs [33,34,36,37] and ideal singlecrystal ZnO bulk mobility (∼200 cm 2 V −1 s −1 ) [29], although one study has stated mobilities in the range of 1200-4120 cm 2 V −1 s −1 [32]. While the origin of these high mobilities is currently unresolved, the SAND dielectric has been observed to provide high performance in a number of channel materials [17,24], so the SAND appears to provide a high quality interface.…”

Fabrication of fully transparent nanowire transistors for transparent and flexible electronics

“…3b,d. These devices exhibit typical enhancement mode long-channel FET [35][36][37][38][39][40] . Because the extraction procedure for m eff involves uncertainties due to the required capacitance estimation (see Methods), NWTs can be compared with planar transistors by comparing the I on and g m per unit width (g m /W), using the nanowire diameter as the device width.…”

ZnO‐Nanowire‐Inserted GaN/ZnO Heterojunction Light‐Emitting Diodes

“…The fabrication and evaluation methods were reported in Refs. 12, 15. The morphology and structural characteristics of the n + ‐ZnO film/n‐ZnO nanowire array/p + ‐GaN film heterojunction diodes were observed by field‐emission SEM (FESEM, Hitachi S4200) with EDX (Kevex SuperDry II) and HRTEM (JEM‐4010).…”

“…The Mg‐doped GaN films exhibited p‐type conductivity with a hole concentration of 1.2×10 18 cm −3 and hole mobility of 15 cm 2 V −1 s −1 . In addition, the evaluated electron concentration of the n‐ZnO nanowires was approximately 10 12 cm −3 12. As a result, the Mg‐doped GaN film/ZnO nanowire structures made nanosized p + –n junctions and a wider depletion region in the n‐ZnO nanowire side was induced compared to that of the p + ‐GaN film side.…”