A metal oxide thin-film transistor and a preparation method therefor. The preparation method comprises the following steps in sequence: a. preparing a metal conducting layer on a substrate and patterning same as a gate electrode; b. depositing a first insulating thin film on the metal conducting layer as a gate insulating layer; c. depositing a metal oxide thin film on the gate insulating layer and patterning same as an active layer; d. depositing a non-metal thin film on the active layer using a physical vapour deposition method as a back-channel etching protective layer; e. depositing a metal layer on the back-channel etching protective layer and then patterning the metal layer as a source/drain electrode pattern; and f. depositing a second insulating thin film on the source/drain electrode as a passivation layer. The preparation process is simple. The prepared metal oxide thin-film transistor has good stability and small size, so that a drive back panel of the metal oxide thin-film transistor can be manufactured at high refinement and low costs.
Recently, exciplexes have been actively investigated in white organic light-emitting diodes (WOLEDs), since they can be effectively functioned as (i) fluorescent or thermally activated delayed fluorescent (TADF) emitters; (ii) the hosts of fluorescent, phosphorescent and TADF dopants. By virtue of the unique advantages of exciplexes, high-performance exciplex-based WOLEDs can be achieved. In this invited review, we have firstly described fundamental concepts of exciplexes and their use in organic light-emitting diodes (OLEDs). Then, we have concluded the primary strategies to develop exciplex-based WOLEDs. Specifically, we have emphasized the representative WOLEDs using exciplex emitters or hosts. In the end, we have given an outlook for the future development of exciplex-based WOLEDs.
A metal oxide thin-film transistor and a preparation method therefor. The preparation method sequentially comprises: a. preparing a metal conducting layer on a substrate (01) and patterning same as a gate electrode (02); b. depositing a first insulating thin film (03) on the metal conducting layer as a gate insulating layer; c. depositing a metal oxide thin film on the gate insulating layer and patterning same as an active layer (04); d. depositing an organic conducting thin film on the active layer as a back-channel etching protective layer (05); e. depositing a metal layer (06) on the back-channel etching protective layer and then patterning same as a graph of a source and a drain electrode; and f. depositing a second insulating thin film on the source and the drain electrode as a passivation layer (07). This present invention has a simple preparation process, and the prepared metal oxide thin-film transistor has good stability and a small size, so that a drive backplane of the metal oxide thin-film transistor can be manufactured at a highly refined level and low cost.
An amorphous metal oxide thin-film transistor and a preparation method therefor. The preparation method sequentially comprises: a. preparing a metal conducting layer on a substrate (01) and patterning same as a gate electrode (02); b. depositing a first insulating thin film (03) on the metal conducting layer as a gate insulating layer; c. depositing an amorphous metal oxide thin film on the gate insulating layer and patterning same as an active layer (04); d. depositing metal on the active layer (04) and patterning same as a source and a drain electrode (05); e. performing stabilization processing on a back channel; and f. depositing a second insulating thin film on the source and the drain electrode (05) as a passivation layer (06). Through the stabilization processing step of the back channel, etching residuals and damage at the back channel can be reduced after etching the source and the drain electrode, the stability of the thin-film transistor can be improved, and the process is simple and the cost is low.
Lu, Jianting
Wei, Aixiang
Zhao, Yu
Tao, Lili
Yang, Yibing
Zheng, Zhaoqiang
Wang, Han
Luo, Dongxiang
Liu, Jun
Tao, Li
Li, Hao
Li, Jingbo
Xu, Jian-Bin
As an emerging 2D nonlayered material, natural defective beta-In2S3 nanosheets have drawn attention because of their unique defective structure and broad optical detection range. Stacking n-type In2S3 with other p-type 2D materials can produce an atomically sharp interface with van der Waals interaction, which may lead to high performance in (opto)electronics. In this study, we fabricated a van der Waals heterostructure composed of In2S3 and graphene via the dry transfer method. Scanning Kelvin probe force microscopy revealed a significant potential difference at the interface of the heterostructure, thereby endowing it with good diode characteristics. The back-gate field effect transistor based on the graphene/In2S3 heterostructure exhibited excellent gate-tunable current-rectifying characteristic with n-type semiconductor behavior. A photodetector based on the graphene/In2S3 heterostructure showed excellent response to visible light. Particularly, an ultrahigh responsivity of 795 A/W and an external quantum efficiency of 2440% are recorded under the illumination of 405 nm light and can be further increased to 8570 A/W and 26 200% with a positive gate voltage of 60 V. The excellent optical responsive performance is attributed to the synergy of photoconductive and photogating effects. These intriguing results suggest that the graphene/In2S3 heterostructure has prospective applications in future electronic and optoelectronic devices.
A series of un-doped and Dy3+ doped Ca9Gd(PO4)(7) phosphors were synthesized by traditional solid state reactions. X-ray diffraction analysis and scanning electronic microscope observation were carried out to examine the phase formation and morphology of prepared samples. Emission spectra under the excitation at 350 nm ultraviolet light turn out that main emission bands are located at 480, 570 and 659 nm, which can be assigned to the optical transitions F-4(9/2) -> H-6(15/2), F-4(9/2) -> H-6(13/2) and F-4(9/2) -> H-6(11/2) of Dy3+, respectively. Comparison of emission spectra upon excitation of 273 nm between un-doped and Dy3+ doped Ca9Gd(PO4)(7) samples proves that effective energy transfer from Gd3+ to Dy3+ takes place. The Commission International de I'Eclairage color coordinates (0.272, 0.322) located in white region was achieved. With the increasing doping concentration of Dy3+, concentration quenching is clearly observed and the optimum content of doped Dy3+ is 0.12. The mechanism of concentration quenching is experimentally ascertained to be electric dipole-dipole interactions. The study of quantum efficiency and thermal stability shows that our phosphors have higher quantum efficiency and better thermal stability. This work indicates that our phosphors have potential applications in white light-emitting diodes.
In this paper, a hydrothermal strategy is developed to synthesize high-quality WSe2 films on a quartz substrate. N, N-dimethylformamide (DMF) and deionized water are used as double solvent, and low-cost selenium powder and sodium tungstate dehydrate are used as the Se and W sources, respectively. Characterizations with X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy confirm the high quality of hexagonal WSe2 films. Photodetectors, which are assembled based on such solution-processed WSe2 films, exhibit a high photoresponsivity and a short response time. This study suggests that WSe2 films are very promising for optoelectronic applications which require low cost, large area and process simplicity.
Recently, thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted both academic and industrial interest due to their extraordinary characteristics, such as high efficiency, low driving voltage, bright luminance, lower power consumption and potentially long lifetime. In this invited review, the fundamental concepts of TADF have been firstly introduced. Then, main approaches to realize WOLEDs based on TADF have been summarized. More specifically, the recent development of WOLEDs based on all TADF emitters, WOLEDs based on TADF and conventional fluorescence emitters, hybrid WOLEDs based on blue TADF and phosphorescence emitters and WOLEDs based on TADF exciplex host and phosphorescence dopants is highlighted. In particular, design strategies, device structures, working mechanisms and electroluminescent processes of the representative WOLEDs based on TADF are reviewed. Finally, challenges and opportunities for further enhancement of the performance of WOLEDs based on TADF are presented.
Luo, Dongxiang
Lan, Linfeng
Xu, Miao
Xu, Hua
Li, Min
Zou, Jianhua
Tao, Hong
Wang, Lei
Peng, Junbiao
Indium-zinc-oxide thin-film transistor (TFT) with a thick aluminum (Al, 1500 nm) gate was demonstrated. The Al gate assembly was planarized by a negative photoresist, and then was further anodized to form a layer of aluminum oxide (Al2O3) as gate dielectric. A good boundary profile between the Al gate and the photoresist was obtained. It was found that increasing the thickness of the Al gate could not only reduce the resistance, but also reduce the hillock density. Furthermore, the TFTs with this buried thick Al gate showed low operation voltage, high mobility, and little threshold voltage shift during gate bias stress. Therefore, it is attractive in large-size, high-resolution flat-panel displays. ((c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Luo, Dongxiang
Li, Min
Xu, Miao
Pang, Jiawei
Zhang, Yanli
Wang, Lang
Tao, Hong
Wang, Lei
Zou, Jianhua
Peng, Junbiao
The stabilities of amorphous indium-zinc-oxide (IZO) thin film transistors (TFTs) with back-channel-etch (BCE) structure are investigated. A molybdenum (Mo) source/drain electrode was deposited on an IZO layer and patterned by hydrogen peroxide (H2O2)-based etchants. Then, after etching the Mo layer, SF6 plasma with direct plasma mode was employed and optimized to improve the bias stress stability. Scanning electron microscopy and X-ray photoelectron spectroscopic analysis revealed that the etching residues were removed efficiently by the plasma treatment. The modified BCE- TFTs showed only threshold voltage shifts of 0.25 V and -0.20 V under positive/negative bias thermal stress (P/NBTS, V-GS = +/- 30 V, V-DS = 0 V and T = 60 degrees C) after 12 hours, respectively. ((c) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Luo, Dongxiang
Lan, Linfeng
Xu, Miao
Xu, Hua
Li, Min
Wang, Lei
Peng, Junbiao
Al-alloys and their anodic oxides were used as the gate and the gate dielectric, respectively, for the indium-zinc-oxide (IZO) thin-film transistors (TFTs). The influence of the Al-alloys on the performances of the IZO-TFTs was investigated. It was found that the hillock formation could be completely suppressed by doping neodymium (Nd) or cerium (Ce) into Al. However, the mobility of the IZO-TFT with Al-Ce gate was only 2 x 10(-4) cm(2) V-1 s(-1), about five orders lower than that of the IZO-TFT with Al-Nd gate (11.6 cm(2) V-1 s(-) (1)). Further analysis showed that Ce3+ and Ce4+ ions were existence in the oxide film obtained by anodizing Al-Ce alloy, and they would diffuse into IZO film. The Ce4+ ion could act as an electron trap due to its strong oxidizability, so the IZO-TFTs with Al-Ce gate would experience seriously degradation. In the case of the oxide film obtain by anodizing Al-Nd alloy, only Nd3+ were found, which was stable and would not produce electron traps. Moreover, the existence of Nd would suppress undesirable free electron formation in the channel, resulting in low off-current, low subthreshold swing, little hysteresis, and high electrical stability under gate bias stress. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.jes038205] All rights reserved.
ITO thin film is hard to be etched in wet etchants because of the crystalline state. To obtain easily-etched transparent conductor oxide (TCO), a layer of ultra-thin IZO was inserted between ITO films. It was found that this as-deposited TCO film with IZO insertion layers was amorphous and easily-etched even in weak acids. Furthermore, the surface roughness of this multilayer TCO film was only 0.52 nm, much lower than that of the ITO monolayer film with the same thickness. After annealing at 250 degree in air, a low sheet resistance of similar to 9.6 Omega/(sic) and a reasonably transmittance of similar to 85% in visible range were obtained. (C) 2013 The Electrochemical Society. All rights reserved.
In this letter, solution-processed flexible zinc-tin oxide (Z(0.35)T(0.65)O(1.7)) thin-film transistors with electrochemically oxidized gate insulators (AlOx:Nd) fabricated on ultra-thin (30 mu m) polyimide substrates are presented. The AlOx:Nd insulators exhibited wonderful stability under bending and excellent insulating properties with low leakage current, high dielectric constant, and high breakdown field. The device exhibited a mobility of 3.9 cm(2)/V.s after annealing at 300 degrees C. In addition, the flexible device was able to maintain the electricity performance under various degrees of bending, which was attributed to the ultra-thin polyimide substrate.
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