High performance of solution-processed SnO₂ thin-film transistors by promotion of photo-exposure time-dependent carrier transport during the pre-annealing stage

Abstract

We fabricate high-performance solution-processed SnO 2 thin-film transistors (TFTs) exhibiting improved carrier transport features by exposing the ultraviolet/ozone (UV/O 3 ) on the SnO 2 film during the pre-annealing stage. The SnO 2 layer is treated with different UV/O 3 -exposure times from 0 to 60 minutes before the post-annealing step. As UV/O 3 -exposure time increases from 0 to 30 minutes, the M-O-M (M, metal; and O, oxygen) network, mass density, and oxygen vacancies of films are enhanced. In contrast, the M-O-M network and mass density decrease, while the oxygen vacancies rather increase when the UV/O 3 -exposure time reaches 60 minutes beyond 30 minutes. The SnO 2 (Sn 4+ ) phase, thickness, and surface morphology of SnO 2 films are not considerably changed regardless of UV/O 3 -exposure time. When the UV/O 3 -exposure time is 30 minutes, devices demonstrate superior field-effect mobility (10.1 cm 2 V −1 s −1 ) at approximately two times higher than the TFT without UV/O 3 -exposure. Furthermore, the SnO 2 TFT with UV/O 3 -exposure time for 30 minutes shows improved subthreshold-swing characteristics and a high on/off current ratio. These devices are adequate for use in high-resolution active-matrix LCDs or OLED displays that demand a high field-effect mobility (>10 cm 2 V −1 s −1 ) and on/off ratio (>10 6 ).

One-Stop Strategy for Obtaining Controllable Sensitivity and Feasible Self-Patterning in Silver Nanowires/Elastomer Nanocomposite-Based Stretchable Ultrathin Strain Sensors

“…UVO, in particular, causes a photochemical reaction known as the Chapman cycle in ambient air. Equations and are related to the formation of ozone, whereas eqs and present the destruction process of ozone normalO 2 → λ 0.25em < 0.25em 240 0.25em nm 2 normalO • normalO • + normalO 2 → normalO 3 normalO 3 → λ 0.25em < 0.25em 300 0.25em nm normalO 2 + normalO • normalO + normalO 3 → 2 normalO 2 …”

“…UVO, in particular, causes a photochemical reaction known as the Chapman cycle in ambient air. Equations and are related to the formation of ozone, whereas eqs and present the destruction process of ozone …”

Dual Role of AgNO3 as an Oxidizer and Chloride Remover toward Enhanced Combustion Synthesis of Low-Voltage and Low-Temperature Amorphous Rare Metal-Free Oxide Thin-Film Transistors

“…19,32 In addition, increased film thickness can also affect mobility since it is proportional to the carrier concentration per unit accumulation area. 24 However, for the 0.10 M Sn concentration, changing the number of layers of the channel did not significantly change the thickness of the film (14.1 and 19.1 nm for the 2 and 3 layers, respectively). This signifies that the 2-layer film is still porous and that the additional layer of spin coating just fills in the holes present in the existing film.…”

“…By using a combustion route, this work aims to produce a good metal oxide network with few chloride and carbon impurities at a low fabrication temperature of 300 °C. In addition, the operating drain voltage usually required to switch on SnO 2 TFT is very high, usually at 20–30 V, due to the Schottky barrier between SnO 2 and Au S/D electrodes. − To drive the operating voltage lower, high- k dielectric materials were employed in SnO 2 TFTs, and others have tried to utilize ultrathin SnO 2 layers as well. − Moreover, previous works on solution-processed SnO 2 TFTs report on V ON values that are always in depletion mode, which means that the transistor is already turned on at negative voltages. ,− In real device applications, this is not ideal because it will require a high energy to turn off the device. By effective control of the carrier concentration, the transistor device can be switched on at a voltage close to zero.…”

“…Studies have reported an increase in the interface traps and bulk traps as the thickness of the active channel material is increased. 24,49 Thus, the SS value was increased and V ON was slightly shifted but was still better compared to the NH 4 NO 3 -assisted TFT that switches on at around −37 V. The other fundamental TFT parameters were also extracted, and they are summarized in Table 3.…”