This paper reports the controlled growth of atomically sharp In O /ZnO and In O /Li-doped ZnO (In O /Li-ZnO) heterojunctions via spin-coating at 200 °C and assesses their application in n-channel thin-film transistors (TFTs). It is shown that addition of Li in ZnO leads to n-type doping and allows for the accurate tuning of its Fermi energy. In the case of In O /ZnO heterojunctions, presence of the n-doped ZnO layer results in an increased amount of electrons being transferred from its conduction band minimum to that of In O over the interface, in a process similar to modulation doping. Electrical characterization reveals the profound impact of the presence of the n-doped ZnO layer on the charge transport properties of the isotype In O /Li-ZnO heterojunctions as well as on the operating characteristics of the resulting TFTs. By judicious optimization of the In O /Li-ZnO interface microstructure, and Li concentration, significant enhancement in both the electron mobility and TFT bias stability is demonstrated.

Hard X-ray photoelectron spectroscopy (HAXPES) has seen continuous development since the first experiments in the 1970s. HAXPES systems are predominantly located at synchrotron sources due to low photoionization cross sections necessitating high X-ray intensities, which limits the technique's availability to a wide range of users and potential applications. Here, a new laboratory-based instrument capable of delivering monochromated X-rays with an energy of 9.25 keV and a microfocused 30 × 45 μm X-ray spot is introduced. The system gives an excellent energy resolution of below 500 meV coupled with good X-ray intensity. It allows stable measurements under grazing incidence conditions to maximise signal intensities. This article outlines the instrument behavior, showcases applications including bulk and multilayer measurements, and describes the overall performance of the spectrometer. This system presents an alternative to synchrotron-based experimental end stations and will help expand the number and range of HAXPES experiments performed in the future.

(1 of 37)high mobility (µ) (even in amorphous phase), wide bandgap (transparent in the visible range), and the ability to be controllably doped. Importantly, they can be grown into thin films and various nanostructures with different scalable deposition techniques, including vacuum-based methods such as physical vapor deposition (PVD) [7,8] and chemical vapor deposition (CVD) [9] as well as solution-based processes such as spray [10] and spin coating. [11] Moreover, the resulting layers can be easily patterned using standard fabrication procedures and as such can be integrated into state-of-the-art processes for (opto)electronic applications. The above-mentioned capabilities have led to a plethora of applications such as switching backplanes for displays, transparent and flexible electronics, integrated circuits (ICs), photovoltaics (PVs), organic light-emitting diodes (OLEDs), capacitors, batteries, photocatalytic devices, electrochromics and memory devices, to name but a few. [8,[12][13][14] Because of their ability to be doped, their electronic properties can be tuned from dielectrics to semiconductors and conductors. This characteristic versatility has recently been exploited to stretch the range of their applications to new technological sectors, such as plasmonics in the near infrared and midinfrared spectral ranges. [12,15] One of the driving applications of metal oxides is in thinfilm transistors (TFTs) for large area electronics such as current driven optical displays and ICs. Following the early demonstrations, [16] most effort focused on the fabrication and processing of metal oxides TFTs paying particular attention to the device performance and applications. [1,5,6,17] Especially when processed over large areas, as in the case for display applications, the complexity to precisely control the device reliability and reproducibility becomes a challenging aspect of any TFT technology. To that respect, solution-based techniques progressed rapidly due to their lower cost and higher throughput compared to vacuum-based techniques. In both cases, the metal-oxide deposition has so far been limited to high processing temperatures (>250 °C) (Figure 1a) which renders the technology incompatible with inexpensive, temperature-sensitive substrates such as polymers, the material class of choice for various high throughput manufacturing techniques such as roll-to-roll (R2R) and sheet-to-sheet (S2S)Over the past few decades, significant progress has been made in the field of photonic processing of electronic materials using a variety of light sources. Several of these technologies have now been exploited in conjunction with emerging electronic materials as alternatives to conventional hightemperature thermal annealing, offering rapid manufacturing times and compatibility with temperature-sensitive substrate materials among other potential advantages. Herein, recent advances in photonic processing paradigms of metal-oxide thin-film transistors (TFTs) are presented with particular emphasis on the use of various light sour...

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We report the fabrication of solution-processed In2O3 and In2O3/ZnO heterojunction thin-film transistors (TFTs) where the precursor materials were converted to their semiconducting state using high power light pulses generated by a xenon flash lamp. In2O3 TFTs prepared on glass substrates exhibited low-voltage operation (≤2 V) and a high electron mobility of ∼6 cm2 V−1 s−1. By replacing the In2O3 layer with a photonically processed In2O3/ZnO heterojunction, we were able to increase the electron mobility to 36 cm2 V−1 s−1, while maintaining the low-voltage operation. Although the level of performance achieved in these devices is comparable to control TFTs fabricated via thermal annealing at 250 °C for 1 h, the photonic treatment approach adopted here is extremely rapid with a processing time of less than 18 s per layer. With the aid of a numerical model we were able to analyse the temperature profile within the metal oxide layer(s) upon flashing revealing a remarkable increase of the layer's surface temperature to ∼1000 °C within ∼1 ms. Despite this, the backside of the glass substrate remains unchanged and close to room temperature. Our results highlight the applicability of the method for the facile manufacturing of high performance metal oxide transistors on inexpensive large-area substrates

The influence of annealing temperature on electron transport in single layer In2O3 and isotype In2O3/ZnO heterojunction channel transistors is investigated.

We report the development of low operating voltages in inorganic-organic hybrid light-emitting transistors (HLETs) based on a solution-processed ZrO gate dielectric and a hybrid multilayer channel consisting of the heterojunction InO/ZnO and the organic polymer "Super Yellow" acting as n- and p-channel/emissive layers, respectively. Resulting HLETs operate at the lowest voltages reported to-date (<10 V) and combine high electron mobility (22 cm/(V s)) with appreciable current on/off ratios (≈10) and an external quantum efficiency of 2 × 10% at 700 cd/m. The charge injection, transport, and recombination mechanisms within this HLET architecture are discussed, and prospects for further performance enhancement are considered.

An efficient way to reduce the supply voltages of organic field-effect transistors is the use of high-k inorganic materials. In order to allow high throughput during fabrication, solution-based processes for realizing inorganic dielectrics by using sol-gel procedures have become attractive in recent years. However, this procedure typically involves extended high-temperature annealing steps to achieve high-quality insulating layers which hampers fast fabrication and is incompatible to be carried out on low-temperature organic substrates. In this work, the use of a photonic curing technique is presented for the annealing of sol-gel derived hafnium oxide (HfO 2 ) dielectrics within a few seconds. The investigations demonstrate the reduction of the leakage current density of more than 3 orders of magnitude after the photonic curing process reaching only slightly higher values as obtained with dielectric films formed from highly sophisticated atomic layer deposition. Moreover, capacitance measurements reveal a dielectric constant of 26 indicating bulk-like properties. Furthermore, organic transistors based on photonically cured HfO 2 sol-gel dielectrics are fabricated and characterized operating at low voltages ( o 2 V), low subthreshold swing (110 mV/decade) and charge carrier mobilities of 1 cm 2 /Vs using a semiconducting liquid-crystal polymer.