Zhao-Hui Li

Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors with a Low-Temperature Polymeric Gate Dielectric on a Flexible Substrate

Amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with a solution-processed polymeric gate dielectric of cross-linked poly(4-vinylphenol) (c-PVP) film were fabricated on a poly(ethylene terephthalate) (PET) substrate on which an a-IGZO film, as the active channel layer, was deposited by radio frequency (RF) sputtering. The entire TFT fabrication process was carried out at a temperature below 110 °C. The device exhibited an on/off ratio of 1.5×106 and a high field-effect mobility of 10.2 cm2 V-1 s-1, which is, to our knowledge, the best result ever achieved among a-IGZO TFTs with polymeric gate dielectrics on a plastic substrate.

Improved Performance of Pentacene Thin-Film Transistors with Al2O3 Gate Dielectric: Annealing Effect on the Surface Properties

We have fabricated pentacene thin-film transistors (TFTs) with modified Al2O3 layers as gate dielectrics. The effects of thermal treatments on the E-beam-processed Al2O3 layers in the TFTs were investigated by using various analytical tools such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscope (AFM), and a contact angle method. From the results of the analyses, it was confirmed that the performance of thermally treated Al2O3 gate dielectrics is much better than that of non-treated ones. Finally, pentacene TFTs were fabricated with optimum conditions and improved electrical properties were obtained for low-voltage (below -3 V) TFTs as follows: a mobility of 0.9 cm2 V-1 s-1, a threshold voltage of -1.3 V, a sub-threshold slope of 0.12 V/decade, and an on/off current ratio of 2.2 ×105.

A Study on the MgO Protective Layer Deposited by Oxygen-Neutral-Beam-Assisted Deposition in AC PDP

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by Ion-Beam-Assisted Deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, Oxygen-Neutral-Beam-Assisted Deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen neutral beam energy of 300eV. The surface morphology of MgO thin film was also analyzed using AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy).

Fabrication of Cu(In,Ga)Se2 Thin Film by Selenization of Stacked Elemental Layer with Solid Selenium

Cu(In,Ga)Se2 thin films were prepared using the classical two-step process approach. In the first step, the metallic precursors were deposited on the soda-lime glass substrates by electron-beam evaporation following the Cu/In/Ga... sequence. The selenization, called the second step, was produced in a rapid thermal processor. This process performed under nitrogen atmosphere of 200 Torr at 200°C for 5 minutes followed by 500°C for 3 minutes. The device quality of CIGS film, with the atomic ratios of Cu/(In+Ga) of 0.90 and Ga/(In+Ga) of 0.26, was obtained when the Cu/In/Ga metallic layer had thinness ratio of 900 A/600 A /200 A. The CIGS film with homogeneous and dense surface morphology with large grain size (~ 2 μm) was formed.

Effect of Laser Scanning Speed on the Laser Direct Patterning of T-shaped Indium Tin Oxide (ITO) Electrode for High Luminous AC Plasma Display Panels

Laser direct patterning is one of new methods which are able to replace a conventional photolithography. In order reduce the fabrication cost and to improve the luminous efficiency of AC plasma display panels (PDPs), in this experiment, a Q-switched Nd: laser was used to fabricate T-shaped indium tin oxide (ITO) display electrodes. For the laser beam scanning speed from 100 mm/sec to 800 mm/sec, T-shaped ITO patterns were clearly obtained and investigated. The experimental results showed that the optimized T-shaped ITO electrode was obtained when the lasers scanning speed was 300 mm/s.

A Study on Discharge Characteristics of the PDP Packaged with In-situ Vacuum Sealing with the MgO Protective Layer Deposited by Optimal Evaporation Rate

AC PDP with MgO protective layer coated with the optimum evaporation rate of can generate more enhanced efficiency through the vacuum in-line sealing process. However, the optimized process conditions still require the optimum driving scheme on the ramp-up and ramp-down slope of the reset waveform for enhancing the efficiency. In this paper, for the in-situ vacuum sealed PDP with the optimum evaporation rate of MgO protective layer, the address delay time was investigated with various slopes of ramp waveform during a reset ramp-up and ramp-down period. In this study, the minimum statistical delay time was obtained at the ramp-up rate of and the ramp-down rate of of the reset waveform.

Structural and Discharge Characteristics of MgO Deposited by Oxygen-Ion-Beam-Assisted Deposition in AC PDP

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). In this paper, we describe the structural and discharge properties of MgO thin films, which were prepared by the ion-beam-assisted deposition (IBAD) of oxygen as the protective layer of PDPs. The energy of the oxygen ion beam was used as the parameter to control the deposition. We found that the oxygen ion beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen ion beam energy of 300 eV. The crystallization of the MgO thin film was also measured by X-ray diffraction analysis, and the surface quality was measured by atomic force microscopy.

Study of a MgO Protective Layer Deposited with Oxygen Ion Beam Assisted Deposition in an AC PDP

MgO layer plays an important role for plasma display panels (PDPs). In this experiment, ion beam assisted deposition (IBAD) methode was uesed to deposit a MgO thin film and the assisting oxygen ion beam energy was varied from 100 eV to 500 eV. In order to investigate the relationship between the secondary electron emission and the defect levels of the MgO layer, we measured the cathodoluminescence (CL) spectra of the MgO thin films, and we analyzed the CL peak intensity and peak transition. The results showed that the assisting ion beam energy played an important role in the peak intensity and the peak transition of the CL spectrum. The properties of MgO thin film were also analyzed using XRD and SEM, these results showed the assisting ion beam energy had direct effect on characteristics of MgO thin film.