Significant improvement of spray pyrolyzed ZnO thin film by precursor optimization for high mobility thin film transistors

Abstract

Metal-oxide thin-film transistors (TFT) fabricated by spray pyrolysis are of increasing interest because of its simple process and scalability. A bottleneck issue is to get a bubble-free and dense material. We studied the effect of ammonium acetate (AA) addition in the oxide precursor solution on the performance of spray-coated ZnO TFTs. AA acts as a stabilizer, which increases the solubility of the solution and enhances the film quality by reducing the defects. With AA addition in ZnO precursor, the films are coffee ring free with high mass density and better grain orientation. The ZnO TFT with AA exhibit a remarkable improvement of its device performance such as saturation mobility increasing from 5.12 to 41.53 cm 2 V −1 s −1 , the subthreshold swing decreasing from 340 to 162 mV/dec and on/ off current ratio increasing from ~10 5 to 10 8. Additionally, the TFTs show excellent stability with a low threshold voltage shift of 0.1 V under gate bias stress. Therefore, the addition of AA is a promising approach to achieve high-performance ZnO TFTs for low-cost manufacturing of displays.

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

“…Therefore, MO, V o , and −OH are deconvoluted separately. [ 1,14,31,39,63 ] According to the binding energy level these subpeaks assigned to metal oxygen (O I ), oxygen vacancy (O II ), and hydroxyl group (O III ). MO, V o , and OH percentage were calculated as O I /(O I + O II + O III ) × 100, O II /(O I + O II + O III )×100, O III /(O I + O II + O III )×100.…”

“…The root mean square roughness ( R RMS ) decreases from 2.4 to 1.21 nm with the absence of coffee rings. [ 14 ] Furthermore, the R RMS decreases from 1.21 to 0.71 nm by Gd doping. The smooth surface of the nanocrystalline GdZnO film indicates that Gd doping in both GdZnO and GdZnO/GI interface could reduce the grain boundary defects.…”

“…Therefore, MO, V o , and −OH are deconvoluted separately. [1,14,31,39,63] According to the binding energy level these subpeaks assigned to metal oxygen ( )×100. We observed the increase of metal-oxygen bond and decrease of V o from MO bonding peak to V o peak ratio.…”

“…ZnO is a well‐known oxide semiconductor because of its excellent electrical and optical properties due to its crystalline structure with high carrier mobility and tunable bandgap by alloying. [ 13,14 ] Although, ZnO TFT has high carrier density with crystalline structure, it has some limitations, such as instabilities. It is known that the instability of pristine ZnO is related to the grain boundary defects related to oxygen vacancy and Zn interstitial.…”

Influence of Inductive Effect in Organic Residuals Content in IZO Thin Films and the Performance on the Behavior of MIS Capacitors on Plastic

“…The origin of the COO-, C-O and O-H bonds are related to the low decomposition of the precursor solution [15]. On the one hand, the presence of these organic residues, such as the C-O bonds, can generate disorder in the film structure and cause surface defects [20,21]. On the other hand, the hydroxyl group plays a role as a charge trap due to its polar nature [18,22].…”