In/Ga-Free, Inkjet-Printed Charge Transfer Doping for Solution-Processed ZnO

Abstract

An In/Ga-free doping method of zinc oxide (ZnO) is demonstrated utilizing a printable charge transfer doping layer (CTDL) based on (3-aminopropyl)triethoxysilane (APS) molecules. The self-assembled APS molecules placed on top of ZnO thin films lead to n-type doping of ZnO and filling shallow electron traps, due to the strong electron-donating characteristics of the amine group in APS molecules. The CTDL doping can tune the threshold voltage and the mobility of the ZnO thin-film transistors (TFTs) as one varies the grafting density of the APS molecules and the thickness of the underneath ZnO thin films. From an optimized condition, high-performance ZnO TFTs can be achieved that exhibit an electron mobility of 4.2 cm(2)/(V s), a threshold voltage of 10.5 V, and an on/off current ratio larger than 10(7). More importantly, the method is applicable to simple inkjet processes, which lead to produce high-performance depletion load ZnO inverters through selective deposition of CTDL on ZnO thin films.

Hybrid Modulation‐Doping of Solution‐Processed Ultrathin Layers of ZnO Using Molecular Dopants

“…Finally, it is noteworthy that our findings for the 15 nm‐thick ZnO are in contradiction to the previously reported results presented by Yu et al who proposed a charge transfer doping effect through the use of self‐assembled monolayers (SAMs) . In the latter study it was suggested that the doping effect vanishes at a ZnO thickness of ≈8 nm, whereas in our 15 nm‐thick ZnO the doping effect is still visible.…”

High electron mobility in thin films formed via supersonic impact deposition of nanocrystals synthesized in nonthermal plasmas

“…While ZnO films comprising nanocrystals have been made [9][10][11][12] , achieving high electron mobility without gating has been elusive. We form thin films comprising these nanocrystals by supersonic expansion and subsequent impaction of the plasma effluent containing the nanocrystals onto suitable substrates.…”

Highly Effective Field-Effect Mobility Amorphous InGaZnO TFT Mediated by Directional Silver Nanowire Arrays

“…Currently, the sputtered and sol-gel amorphous indium-gallium-zinc oxide (a-IGZO) TFTs have a typical effective mobility in the range of 10-40 cm 2 /Vs and 1-14 cm 2 /Vs, respectively. 3,[5][6][7][8] Together with a large energy bandgap (> 3eV) to enable the transparency property, AOS TFTs are promising for developing flexible and transparent electronic devices. [9][10][11] Current developments of AOS TFTs have been focused on increasing the effective mobility, i.e.…”