Reliable Operation in High-Mobility Indium Oxide Thin Film Transistors.

Transparent oxide semiconductors (TOSs) based thin-film transistors (TFTs) that exhibit higher field effect mobility (µ) are highly required toward the realization of next-generation displays. Among numerous types of TOS-TFTs, InO-based TFTs are the front-running candidate because they exhibit the highest µ ≈100 cm V s. However, the device operation of InO TFTs is unreliable; a large voltage shift occurs especially when negative gate bias is applied due to adsorption/desorption of gas molecules.

Solid-State Electrochemical Thermal Switches with Large Thermal Conductivity Switching Widths.

Thermal switches that switch the thermal conductivity (κ) of the active layers are attracting increasing attention as thermal management devices. For electrochemical thermal switches, several transition metal oxides (TMOs) are proposed as active layers. After electrochemical redox treatment, the crystal structure of the TMO is modulated, which results in the κ switching.

Influence of Grain Boundary Scattering on the Field-Effect Mobility of Solid-Phase Crystallized Hydrogenated Polycrystalline InO (InO:H).

Hydrogenated polycrystalline InO (InO:H) thin-film transistors (TFTs) fabricated via the low-temperature solid-phase crystallization (SPC) process with a field-effect mobility () exceeding 100 cm V s are promising candidates for future electronics applications. In this study, we investigated the effects of the SPC temperature of Ar + O + H-sputtered InO:H films on the electron transport properties of InO:H TFTs. The InO:H TFT with an SPC temperature of 300 °C exhibited the best performance, having the largest of 139.

High-mobility hydrogenated polycrystalline InO (InO:H) thin-film transistors.

Oxide semiconductors have been extensively studied as active channel layers of thin-film transistors (TFTs) for electronic applications. However, the field-effect mobility (μ) of oxide TFTs is not sufficiently high to compete with that of low-temperature-processed polycrystalline-Si TFTs (50-100 cmVs). Here, we propose a simple process to obtain high-performance TFTs, namely hydrogenated polycrystalline InO (InO:H) TFTs grown via the low-temperature solid-phase crystallization (SPC) process.

Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications.

Low-temperature activation of oxide semiconductor materials such as In-Ga-Zn-O (IGZO) is a key approach for their utilization in flexible devices. We previously reported that the activation temperature can be reduced to 150 °C by hydrogen-doped IGZO (IGZO:H), demonstrating a strong potential of this approach. In this paper, we investigated the mechanism for reducing the activation temperature of the IGZO:H films.

Nondegenerate Polycrystalline Hydrogen-Doped Indium Oxide (InO:H) Thin Films Formed by Low-Temperature Solid-Phase Crystallization for Thin Film Transistors.

We successfully demonstrated a transition from a metallic InO film into a nondegenerate semiconductor InO:H film. A hydrogen-doped amorphous InO:H (a-InO:H) film, which was deposited by sputtering in Ar, O, and H gases, could be converted into a polycrystalline InO:H (poly-InO:H) film by low-temperature (250 °C) solid-phase crystallization (SPC). Hall mobility increased from 49.

Record-High-Performance Hydrogenated In-Ga-Zn-O Flexible Schottky Diodes.

High-performance In-Ga-Zn-O (IGZO) Schottky diodes (SDs) were fabricated using hydrogenated IGZO (IGZO:H) at a maximum process temperature of 150 °C. IGZO:H was prepared by Ar + O + H sputtering. IGZO:H SDs on a glass substrate exhibited superior electrical properties with a very high rectification ratio of 3.

Quantum Confinement Effect in Amorphous In-Ga-Zn-O Heterojunction Channels for Thin-Film Transistors.

Electrical and carrier transport properties in In-Ga-Zn-O thin-film transistors (IGZO TFTs) with a heterojunction channel were investigated. For the heterojunction IGZO channel, a high-In composition IGZO layer (IGZO-high-In) was deposited on a typical compositions IGZO layer (IGZO-111). From the optical properties and photoelectron yield spectroscopy measurements, the heterojunction channel was expected to have the type-II energy band diagram which possesses a conduction band offset (Δ) of ~0.

Memristive Characteristic of an Amorphous Ga-Sn-O Thin-Film Device with Double Layers of Different Oxygen Density.

We have found a memristive characteristic of an amorphous Ga-Sn-O (α-GTO) thin-film device with double layers of different oxygen density. The double layers are deposited using radio frequency (RF) magnetron sputtering, whose gas for the lower layer contains less oxygen, whereas that for the upper layer contains more oxygen, and it is assumed that the former contains more oxygen vacancies, whereas the latter contains fewer vacancies. The characteristic is explained by drift of oxygen and is stable without forming operation because additional structures such as filament are unnecessary.

Memristive characteristic of an amorphous Ga-Sn-O thin-film device.

We have found a memristive characteristic of an α-GTO thin-film device. The α-GTO thin-film layer is deposited using radio-frequency (RF) magnetron sputtering at room temperature and sandwiched between the Al top and bottom electrodes. It is found that the hysteresis loop of the flowing current (I) and applied voltage (V) characteristic becomes larger and stable after the one hundredth cycle.