58 research outputs found
Effect of plasma surface pre-treatment on plastic substrate for ZnO TFT
Controlling the surface morphologies of ZnO
nanostructures is a critical issue for the fabrication of
electronic and photonic devices. This study reports the
electrical properties of the ZnO nanostructure grown on the
plasma surface pre-treated plastic substrates. The ZnO films
were grown by using solution method with zinc nitrate
hexahydrate Zn(NO3)2•6H2O and hexamethylenetetramine
C12H6N4.as the main solution under various deposition
conditions. The films with plasma surface pre-treatment has
stronger (100) peak intensity than that without plasma surface
pre-treatment. Also, very uniform grain size of the ZnO
nanostructures can be seen. The fabricated enhancement mode
ZnO thin film transistors (TFTs) exhibiting good transistor
behavior with the drain saturation current of 38.1 µA at VGS =
35 V can be achieved.
Keywords: ZnO nanostructure, plastic substrate, solution
method, plasma, surface pre-treatment, TFT
High-Mobility Pentacene-Based Thin-Film Transistors With a Solution-Processed Barium Titanate Insulator
Abstract—Pentacene-based organic thin-film transistors
(OTFTs) with solution-processed barium titanate (Ba1.2Ti0.8O3)
as a gate insulator are demonstrated. The electrical properties
of pentacene-based TFTs show a high field-effect mobility of
8.85 cm2 · V−1 · s−1, a low threshold voltage of −1.89 V, and a
low subthreshold slope swing of 310 mV/decade. The chemical
composition and binding energy of solution-processed barium
titanate thin films are analyzed through X-ray photoelectron
spectroscopy. The matching surface energy on the surface of
the barium titanate thin film is 43.12 mJ · m−2, which leads to
Stranski–Krastanov mode growth, and thus, high mobility is
exhibited in pentacene-based TFTs.
Index Terms—Barium titanate, high field-effect mobility, high
permittivity, organic thin-filmtransistor (OTFT), solution process
Pentacene-Based Thin-Film Transistors With a Solution-Process Hafnium Oxide Insulator
Abstract—Pentacene-based organic thin-film transistors with
solution-process hafnium oxide (HfOx) as gate insulating layer
have been demonstrated. The solution-process HfOx could not
only exhibit a high-permittivity (κ = 11) dielectric constant but
also has good dielectric strength. Moreover, the root-mean-square
surface roughness and surface energy (γs) on the surface of the
HfOx layer were 1.304 nm and 34.24 mJ/cm2, respectively. The
smooth, as well as hydrophobic, surface of HfOx could facilitate
the direct deposition of the pentacene film without an additional
polymer treatment layer, leading to a high field-effect mobility of
3.8 cm2/(V · s).
Index Terms—Hafnium oxide, high permittivity, organic thinfilm transistor (OTFT), solution process, surface energy
Improved Reliability of Small Molecule Organic Solar Cells by Double Anode Buffer Layers
An optimized hybrid planar heterojunction (PHJ) of small molecule organic solar cells (SM-OSCs) based on copper phthalocyanine (CuPc) as donor and fullerene (C60) as acceptor was fabricated, which obviously enhanced the performance of device by sequentially using both MoO3 and pentacene as double anode buffer layers (ABL), also known as hole extraction layer (HEL). A series of the vacuum-deposited ABL, acting as an electron and exciton blocking layer, were examined for their characteristics in SM-OSCs. The performance and reliability were compared between conventional ITO/ABL/CuPc/C60/BCP/Ag cells and the new ITO/double ABL/CuPc/C60/BCP/Ag cells. The effect on the electrical properties of these materials was also investigated to obtain the optimal thickness of ABL. The comparison shows that the modified cell has an enhanced reliability compared to traditional cells. The improvement of lifetime was attributed to the idea of double layers to prevent humidity and oxygen from diffusing into the active layer. We demonstrated that the interfacial extraction layers are necessary to avoid degradation of device. That is to say, in normal temperature and pressure, a new avenue for the device within double buffer layers has exhibited the highest values of open circuit voltage (Voc), fill factor (FF), and lifetime in this work compared to monolayer of ABL
Effect of Alkaline Earth Metal on AZrO<sub>x</sub> (A = Mg, Sr, Ba) Memory Application
Zr can be stabilized by the element selected, such as Mg-stabilized Zr (MSZ), thus providing MSZ thin films with potentially wide applications and outstanding properties. This work employed the element from alkaline earth metal stabilized Zr to investigate the electrical properties of sol–gel AZrOx (A = alkaline earth metal; Mg, Sr, Ba) as dielectric layer in metal-insulator–metal resistive random-access memory devices. In addition, the Hume–Rothery rule was used to calculate the different atomic radii of elements. The results show that the hydrolyzed particles, surface roughness, and density of oxygen vacancy decreased with decreased difference in atomic radius between Zr and alkaline earth metal. The MgZrOx (MZO) thin film has fewer particles, smoother surface, and less density of oxygen vacancy than the SrZrOx (SZO) and BaZrOx (BZO) thin films, leading to the lower high resistance state (HRS) current and higher ON/OFF ratio. Thus, a suitable element selection for the sol–gel AZrOx memory devices is helpful for reducing the HRS current and improving the ON/OFF ratio. These results were obtained possibly because Mg has a similar atomic radius as Zr and the MgOx-stabilized ZrOx
Effects of Different Anti-Solvents and Annealing Temperatures on Perovskite Thin Films
Since perovskite materials are currently mostly used in the active layer of solar cells, how to maximize the conversion efficiency of the active layer is the most urgent problem at present. In this regard, the extremely low voltage loss and tunable energy gap of methyl lead iodide (MAPbI3) perovskites make them very suitable for all perovskite solar cell applications, and are also compatible with silicon crystalline systems. Therefore, the future development of MAPbI3 perovskite will be very important. The key point of film formation in MAPbI3 is the addition of anti-solvent, which will affect the overall quality of the film. Whether it can be used as an excellent active layer to improve the application value will be very important. Therefore, the research purpose of this topic “Effects of different anti-solvents and annealing temperatures on perovskites” is to complete the basic research and development of a light-absorbing layer of a solar cell element, in which three different anti-solvents need to be matched with each other as the active light-absorbing layer of a solar cell. Through optimization, using the chemical properties of different anti-solvents and different annealing temperatures, combined with the low-process-cost characteristics of organic materials and many other advantages, we researched the optimized process methods and parameters to improve the absorption efficiency of the active light-absorbing layer
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