A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.

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Ultrasensitive photodetectors based on monolayer MoS2.

Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which has led to the fabrication of high performance n- and p-type oxide transistors as well as the fabrication of CMOS devices with and on paper.

Oxide Semiconductor Thin‐Film Transistors: A Review of Recent Advances

In this paper, recent progress of binary metal-oxide resistive switching random access memory (RRAM) is reviewed. The physical mechanism, material properties, and electrical characteristics of a variety of binary metal-oxide RRAM are discussed, with a focus on the use of RRAM for nonvolatile memory application. A review of recent development of large-scale RRAM arrays is given. Issues such as uniformity, endurance, retention, multibit operation, and scaling trends are discussed.

Metal–Oxide RRAM

Over the past 25 years, organic field-effect transistors (OFETs) have witnessed impressive improvements in materials performance by 3–4 orders of magnitude, and many of the key materials discoveries have been published in Advanced Materials. This includes some of the most recent demonstrations of organic field-effect transistors with performance that clearly exceeds that of benchmark amorphous silicon-based devices. In this article, state-of-the-art in OFETs are reviewed in light of requirements for demanding future applications, in particular active-matrix addressing for flexible organic light-emitting diode (OLED) displays. An overview is provided over both small molecule and conjugated polymer materials for which field-effect mobilities exceeding > 1 cm2 V–1 s–1 have been reported. Current understanding is also reviewed of their charge transport physics that allows reaching such unexpectedly high mobilities in these weakly van der Waals bonded and structurally comparatively disordered materials with a view towards understanding the potential for further improvement in performance in the future.

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25th anniversary article: organic field-effect transistors: the path beyond amorphous silicon.

This review covers important advances in recent years in the physics of thin-film ferroelectric oxides, the strongest emphasis being on those aspects particular to ferroelectrics in thin-film form. The authors introduce the current state of development in the application of ferroelectric thin films for electronic devices and discuss the physics relevant for the performance and failure of these devices. Following this the review covers the enormous progress that has been made in the first-principles computational approach to understanding ferroelectrics. The authors then discuss in detail the important role that strain plays in determining the properties of epitaxial thin ferroelectric films. Finally, this review ends with a look at the emerging possibilities for nanoscale ferroelectrics, with particular emphasis on ferroelectrics in nonconventional nanoscale geometries.

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Physics of thin-film ferroelectric oxides

We fabricated lanthanum indium zinc oxide (IZO) (La-IZO) thin-film transistors (TFTs) using radio frequency cosputtering of IZO and lanthanum. The field-effect mobility and switching ratio of the La-IZO TFTs were 4.2 cm2·V-1·s-1 and on the order of 108, respectively, before thermal annealing and 3.02 cm2·V-1·s-1 and on the order of 1010, respectively, after thermal annealing at 150°C in air. Our La-IZO TFTs had better thermal stability than pure-IZO TFTs due to the stable ionic bond between La and O.

Low-Temperature Fabrication and Characteristics of Lanthanum Indium Zinc Oxide Thin-Film Transistors

In this study, we investigate the instability of amorphous oxide thin film transistors using hafnium-indium-zinc oxide under simultaneous application of light and gate dc-bias. The hump characteristics are observed after negative gate bias and light stress. Based on the positive bias-induced recovery, it is proved that photo-generated holes are trapped in the gate insulator by the electrical field enhanced by the optical energy. Moreover, from simulated electric field distribution, it is clearly revealed that the hole-trapping is localized at the edge regions of the gate insulator along channel width/length directions by electric field crowding, resulting in the hump occurrence.

Investigation on the characteristics of stress-induced hump in amorphous oxide thin film transistors

A novel amorphous oxide TFT Enhancement/Depletion (E/D) inverter through uni-/bi-layer channel hybrid integration with conventional process is demonstrated. The device's threshold voltages (V th ) is strictly controlled and the fabrication technique is specially designed. Comparing to the reported high speed bootstrapped inverter, the output swing, switching voltage gain and noise margin of E/D inverter are greatly improved and only the ring oscillator's speed is slightly degraded while with a small supply voltage of 5V.

High performance low voltage amorphous oxide TFT Enhancement/Depletion inverter through uni-/bi-layer channel hybrid integration

We have investigated the impact of high-k HfO2 gate dielectric on the low-frequency noise (LFN) behaviors of amorphous indium–gallium–zinc oxide thin-film transistors by comparing the LFNs of devices with SiO2 and HfO2 dielectrics. Measured LFNs are nearly 1/ f type for both devices, but the normalized noise for the HfO2 device is around one order of magnitude higher than that for the SiO2 device. The bulk mobility fluctuation is considered as the dominant LFN mechanism in both devices, and the increased LFN in the HfO2 device is attributed to the enhanced mobility fluctuation by the remote phonon scattering from the HfO2.

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Impact of High-k HfO2 Dielectric on the Low-Frequency Noise Behaviors in Amorphous InGaZnO Thin Film Transistors

A multilevel one-time programmable (OTP) oxide diode for cross-point memory is introduced. The oxide diode is composed of a thin-film p-CuO/n-InZnOx (IZO). By applying negative electrical pulses, the p-CuO/n-IZO diode exhibited multilevel resistance states, and such characteristics of the p-CuO/n-IZO diode could be utilized as the cell of OTP cross-point memory. The resistance-change properties of the p-CuO/n-IZO diode originated possibly from a back-to-back diode phenomenon by oxygen ion migration in the IZO thin film.

Chang Jung Kim

Papers

Low-Temperature Fabrication and Characteristics of Lanthanum Indium Zinc Oxide Thin-Film Transistors

Investigation on the characteristics of stress-induced hump in amorphous oxide thin film transistors

High performance low voltage amorphous oxide TFT Enhancement/Depletion inverter through uni-/bi-layer channel hybrid integration

Impact of High-k HfO2 Dielectric on the Low-Frequency Noise Behaviors in Amorphous InGaZnO Thin Film Transistors

Multilevel Programmable Oxide Diode for Cross-Point Memory by Electrical-Pulse-Induced Resistance Change