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Virtual reality, augmented reality, quantum dot light-emitting diodes, and organic light-emitting diodes have progressed over the last two years. Key achievements in these displays are discussed in terms of device performance.

The remarkable progress of virtual reality, augmented reality, quantum dot light-emitting diode, and organic light-emitting diode as next-generation displays has overcome the leadership of the liquid crystal display during the last two years. This paper discusses the key technological advancements and performance of these new-generation display devices.

Herein, this study reports scalable and selective n-type conversion (N/C) approach for single walled carbon nanotube (SWNT) transistors with high reproducibility by using novel control of hydroxyl groups through condensation on the surface of SWNTs, via the patternable cross-linked polyvinyl alcohol (C-PVA), followed by encapsulation of photo-definable hydrophobic polymer (~SU8). Moreover, N/C process capability is statistically evaluated in terms of selective doping, process yield, and statistical variation in electrical parameters, and as practical validation, complementary inverters, NOR and NAND logic gates are fully demonstrated. As one of key findings, it is elucidated that N/C uniformity and its underlying physics, supported by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis, are highly correlated with ambient condition, C-PVA thickness, and encapsulation. More practically, reproducible field effect mobility for n-type (or p-type) SWNT TFTs after (or before) N/C are achieved at ~ 3.65 ± 1.30 (or 8.76 ± 2.16) cm2 V−1 s−1, with magnificent process yield (~100%) and reasonable mobility reduction, which is on par with the previous report. Hence, all demonstration and their analyses suggest that this scalable N/C scheme for SWNT TFTs can be one of core technologies for the next generation semiconductor-based devices and their envisioned application.

This paper aims to discuss the key accomplishments and further prospects of active-matrix (AM) quantum-dot (QD) light-emitting diodes (QLEDs) display. We present an overview and state-of-the-art of QLEDs as a frontplane and non-Si-based thin-film transistors (TFTs) as a backplane to meet the requirements for the next-generation displays, such as flexibility, transparency, low power consumption, fast response, high efficiency, and operational reliability. After a brief introduction, we first review the research on non-Si-based TFTs using metal oxides, transition metal dichalcogenides, and semiconducting carbon nanotubes as the driving unit of display devices. Next, QLED technologies are analyzed in terms of the device structure, device engineering, and QD patterning technique to realize high-performance, full-color AM-QLEDs. Lastly, recent research on the monolithic integration of TFT–QLED is examined, which proposes a new perspective on the integrated device. We anticipate that this review will help the readership understand the fundamentals, current state, and issues on TFTs and QLEDs for future AM-QLED displays.

The authors demonstrate the enhancement mode p-type SnO thin-film transistors (TFTs) using dual gate (DG) structures. The cross-linked polyvinyl alcohol dielectric with a polymethylmethacrylate buffer layer is formed as a top gate (TG) insulator of the DG SnO TFT. The fabricated DG SnO TFT exhibits better electrical performances than the bottom gate (BG) and TG SnO TFTs including higher field-effect mobility and smaller subthreshold slope. In fabricated DG TFTs, the threshold voltage (Vth) of the BG TFT is linearly modulated by the voltage applied to the TG electrode. The BG transfer curve exhibits a depletion mode operation when measured while TG is grounded, but operates in the enhancement mode with a negative Vth (=-0.9 V) when a positive bias of 10V is applied to the TG electrode. The enhancement mode operation of p-type SnO TFTs can increase the output voltage swing range and decreases the off-stage leakage currents of the complementary logic circuits. [ABSTRACT FROM AUTHOR]

This paper investigates the low-frequency noise properties of multilayer WSe2 field effect transistors (FETs) in subthreshold, linear, and saturation regime. The measured noise power spectral density of drain current (SID) shows that the low-frequency noise in multilayer WSe2 FET fits well to a 1/fγ power law with γ ~ 1 in the frequency range of 10Hz-200Hz. From the dependence of SID on the drain current, carrier mobility fluctuation is considered as a dominant low frequency noise mechanism from all operation regimes in multilayer WSe2 FET. Extracted Hooge's parameter in this study is within the value of 0.12, comparable to those of the transition metal dichalcogenide FETs in recent reports. [ABSTRACT FROM AUTHOR]

In this letter, spray-coated single walled carbon nanotubes (SWNTs) as one of alternative electrodes in SnO thin-film transistors are demonstrated for emerging electronic applications. Herein, the device architecture of SnO TFTs with a polymer etch stop layer (SU-8) enables the selective etching of SWNTs in a desired region without the detrimental effects of SnO channel layers. Moreover, SnO TFTs with SWNT electrodes as substitutes successfully demonstrate decent width normalized electrical contact properties (∼1.49 kΩ cm), field effect mobility (∼0.69 cm2 V−1 s−1), sub-threshold slope (∼0.4 V dec−1), and current on–off ratio (Ion/Ioff ∼ 3.5 × 103). Systematic temperature dependency measurements elucidate that SnO channel transports with an activation energy within several tens of meV, together with decent contact resistance as compared to that of conventional Ni electrodes. [ABSTRACT FROM AUTHOR]

We demonstrated highly stable multilayer molybdenum disulfide (MoS2) field-effect transistors (FETs) with negligible hysteresis gap (ΔVHYS ∼ 0.15 V) via a multiple annealing scheme, followed by systematic investigation for long-term air stability with time (∼50 days) of MoS2 FETs with (or without) CYTOP encapsulation. The extracted lifetime of the device with CYTOP passivation in air was dramatically improved from 7 to 377 days, and even for the short-term bias stability, the experimental threshold voltage shift, outstandingly well-matched with the stretched exponential function, indicates that the device without passivation has approximately 25% larger the barrier distribution (ΔEB = kBTo) than that of a device with passivation. This work suggests that CYTOP encapsulation can be an efficient method to isolate external gas (O2 and H2O) effects on the electrical performance of FETs, especially with low-dimensional active materials like MoS2. [ABSTRACT FROM AUTHOR]