Synthesis of a Tellurium Semiconductor with an Organic–Inorganic Hybrid Passivation Layer for High-Performance p-Type Thin Film Transistors

Abstract

Development of high-performance p-channel devices is in high demand for implementing complementary metal-oxide semiconductor logic circuits. In this study, we propose a synthetic approach to high-performance p-type tellurium (Te) thin-film transistors (TFTs) passivated with an organic–inorganic hybrid passivation layer. A quasi-two-dimensional Te channel is synthesized by the sputtering system at room temperature, and an organic–inorganic hybrid passivation layer is formed via infiltration of the synthesis process, including diffusion and infiltration of inorganic Al2O3 into an SU-8 polymeric template, resulting in a high-performance p-type Te TFT with a field-effect mobility of 13.6 cm2/(V s), a subthreshold swing of 6.15 V/decade, and a current on–off ratio of 1.35 × 104. The synergistic effect of Al2O3 and SU-8 is systematically analyzed by implementing devices with hybrid passivation layers, enabling a significant improvement in the device performance compared with that of the device passivated with a single Al2O3 layer. Based on the chemical states and Raman response of the proposed structure, the reduction of oxidative Te states and the strain-induced shifts of the Raman modes are shown to attribute to the compensation for the thermal expansion mismatch and the decrease in the strain-induced damage, leading to enhanced device performance with excellent long-term stability over 70 days in the air. Thus, our work demonstrates the great potential of high-performance p-type Te TFTs for future electronic applications.

Effects of solution processable CuI thin films with Al2O3-based sandwiched architecture for high-performance p-type transistor applications

“…The enhancement in the device performance can be ascribed to the reducing role of the hydrogen that is diffused from the ALD-grown Al 2 O 3 interfacial layer to the CuI channel layer and generates the I Vac s. This can lead to a decrease in the hole concentration and an improved crystallinity, and eventually, an enhanced device performance, where the I Vac s can act as a donor state in the CuI TFTs. 29,37,46 A slight shift of V TH in the negative direction was observed in the device with a 20 nm-thick-Al 2 O 3 interfacial layer owing to the decrease in the hole concentration. The positive V TH value of the device operating in depletion mode can be attributed to the huge amount of hole concentration in the CuI channel, which needs to be modulated further to achieve the low power consumption device.…”

A Mixture of Negative-, Zero-, and Positive-Differential Transconductance Switching from Tellurium/Indium Gallium Zinc Oxide Heterostructures

“…Figure g shows the O1 s XPS spectra from the annealed IGZO layer. The large single peak, which includes O 2 ion peak and O vacancy peak at 531.3 and 532.7 eV, respectively, indicates that the prepared IGZO possesses excellent n -type semiconductor characteristics based on their huge O vacancy peak. , The prepared Te and IGZO layers show narrow-band gap semiconductor and n -type semiconductor band properties, extracted from the UPS, UV–vis, and electrical characteristics depending on annealing temperature results, as shown in Figures S3–S5. Especially, the annealing process is crucial to control the mobility and threshold voltage of the Te/IGZO heterostructure, as shown in Figure S6.…”

Promotion of Processability in a p-Type Thin-Film Transistor Using a Se–Te Alloying Channel Layer

“…The N trap continuously decreased from 3.8 × 10 13 to 8.1 × 10 12 cm –2 ·eV –1 with increasing annealing temperature to 250 °C. The N trap was extracted according to eq . , SS = italickT nobreak0em0.1em⁡ ln nobreak0em0.25em⁡ 10 q [ 1 + q 2 C N t r a p ] where k is the Boltzmann constant, T is the absolute temperature, q is the electron charge, and C is the dielectric capacitance per unit area.…”

“…Recently, a new class of low-dimensional material, Te, has been intensively studied as a channel material for pTFT. − Te atoms are covalently bonded with the two nearest atoms, constructing one-dimensional (1D) helical chains along the [001] direction. Each 1D helical chain is bonded by van der Waals interaction, forming hexagonal crystal arrays. , The band gap ( E g ) of the Te film can be continuously modulated from 0.35 to 1.3 eV with the reduction in film thickness due to the quantum confinement effect. , To achieve an E g over 0.7 eV, necessary for a TFT channel layer to ensure I off , the Te film must be less than 10 nm thick. − However, uniformly depositing a few nanometer-thin Te film is technically challenging through conventional physical and chemical vapor deposition processes that use an island growth mechanism. Moreover, achieving a well-crystalline-oriented Te film continuously grown with a few nm thickness over a 4-in.…”