VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2024-03-29T07:55:51ZEPrintshttp://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/2018-11-24T01:58:46Z2018-11-24T01:58:46Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3001This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30012018-11-24T01:58:46ZInvestigation on solution-processed In-Si-O thin film transistor via spin-coating methodIn this work, we have explored optimum fabrication condition by a solution processing method for 3 at.% Si doped indium oxide thin-film transistors (TFTs). In-Si-O (ISO) thin films were investigated by X-ray reflectivity (XRR) and X-ray diffraction (XRD) techniques, and the operation of TFTs were characterized by a conventional three-probe method. XRR results suggested that as the annealing temperature increased, the film thickness decreased. In addition, according to XRD measurement, the ISO film started crystalline from 850 °C regardless the film thickness. The best ISO TFT showed the value of VT of –5 V, µ of 1.32 cm2/Vs, SS of 1 V/dec, and on/off current ratio about 107.Ha HoangTatsuki HoriTo-oru YasudaTakio KizuKazuhito TsukagoshiToshihide NabatameNguyen Quoc Trinh Buitrinhbnq@vnu.edu.vnAkihiko Fujiwara2018-11-20T09:05:19Z2018-11-20T09:05:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3164This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/31642018-11-20T09:05:19ZSi-doping effect on solution-processed In-O thin-film transistorsIn this work, silicon-doped indium oxide thin-film transistors (TFTs) have been fabricated for the first
time by a solution processing method. By varying the Si concentration in the In2O3–SiO2 binary oxide
structure up to 15 at%, the thicknesses, densities, and crystallinity of the resulting In–Si–O(ISO) thin
films were investigated by x-ray reflectivity (XRR) and x-ray diffraction techniques, while the
produced TFTs were characterized by a conventional three-probe method. The results of XRR analysis
revealed that the increase in the content of Si dopant increased the thickness of the produced film and
reduced its density, and that all the Si-doped ISO thin films contained only a single amorphous phase
even after annealing at temperatures as high as 800 °C. The manufactured ISO TFTs exhibited a
reduction in the absolute value of threshold voltage VT close to 0 Vand low current in the off-state, as
compared to those of the non-doped indium oxide films, due to the reduced number of oxygen
defects, which was consistent with the behavior of ISO TFTs fabricated by a sputtering method. The
ISO TFT with a Si content of 3 at% annealed at 400 °Cdemonstrated the smallest subthreshold swing
of 0.5 V/dec, VT of−5 V, mobility of 0.21 cm2 V−1s−1, and on/off current ratio of about 2×107.Ha HoangTatsuki HoriTo-oru YasudaTakio KizuKazuhito TsukagoshiToshihide NabatameNguyen Quoc Trinh BuiAkihiko Fujiwara2018-01-03T07:25:27Z2018-01-03T07:25:27Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2893This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28932018-01-03T07:25:27ZEpitaxial-like growth of solution-processed PbZr0.4Ti0.6O3 thin film on single-crystal Nb-doped SrTiO3 substratePbZr0.4Ti0.6O3 (PZT) thin films have been conventionally fabricated on traditional silicon substrates with a platinum bottom electrode; however, as a consequence of unit cell mismatch, the films are difficult to form as an epitaxial-like growth. Hence, PZT films deposited on single-crystal niobium doped SrTiO3(111) substrates (Nb:STO) are promising to solve this issue thanks to the similar perovskite structure between PZT and STO. Essentially, Nb:STO material is a conductor, playing a part in both bottom electrode and epitaxial substrate. In this work, 200-nm-thick PZT films were successfully fabricated on Nb:STO substrates by a solution process. One obtained that PZT(111) peak started to appear on the Nb:STO substrate at a low annealing temperature of 450oC. Also, scanning electron microscopy observation shows smooth and homogeneous surface of PZT films on Nb:STO substrate with no grain boundary, which evidences for epitaxial-like growth of PZT thin films. Remnant polarization of 6 µC/cm2 and leakage current of 8×10-8 A were obtained at applied voltage of 5 V.Ha HoangNguyen Quoc Trinh Buitrinhbnq@vnu.edu.vn2017-11-16T04:26:31Z2017-11-16T04:26:31Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2633This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/26332017-11-16T04:26:31ZSTUDY ON ITO THIN FILMS PREPARED BY
MULTI-ANNEALING TECHNIQUEIndium tin oxide (ITO) thin films have been successfully prepared by a solution process
followed by a multi-annealing method. In this study, we focus on the use of multi-annealing
method, for which each layer was annealed at a suitable temperature, instead of a conventional
annealing way, by means of a rapid thermal annealing system, in order to improve the film
quality. The crystalline structure and surface morphology of the ITO thin films were investigated
by using X-ray diffraction (XRD) spectrometer, atomic force microscope (AFM) and scanning
electron microscope (SEM). It has been obtained that all of ITO films exhibit a single phase with
(200)- and (444)-preferred orientations. The AFM and SEM observations show that the particle
size of ITO films was about 10 nm and the ITO film thickness was 180 nm, respectively. In
sequence, the electrical properties of ITO thin films were evaluated by using four-point probe
and Hall effect measurement methods, and the optical properties were investigated by UV/VIS
spectrometer. The achievement results show that the optimum ITO films possessed electrical
resistivity of 2.6 × 10-3 Ωcm and transparency higher than 90%, which strongly supports to the
application of electrode in solar cell, LED or transistor devices from viewpoints of low-cost
production and low-energy consumption.Quang Hoa NguyenThi Xuyen NguyenQuoc Viet VuongThi Huyen Trang VuHa HoangThi Thanh Tam HoangThi Dung VuVan Dung TranNguyen Quoc Trinh Buitrinhbnq@vnu.edu.vn2017-11-16T04:26:10Z2017-11-16T04:26:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2632This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/26322017-11-16T04:26:10ZINVESTIGATION ON STRUCTURAL AND FERROELECTRIC PROPERTIES OF Bi3.25La0.75Ti3O12 THIN FILMSLanthanum doped bismuth titanate (Bi3.25La0.75Ti3O12 abbreviated as BLT) has been known
as one of typical materials for Bi-layered perovskite structure which possess several unique
properties such as good fatigue with metal electrode and stable remanent polarization, hence it
has potential applications in ferroelectric random access memory. In this work, the BLT thin
films were fabricated on Pt/TiO2/SiO2/Si substrates by using a solution process, and then their
features including crystal structure, surface morphology, and electrical properties were
characterized by using X-ray diffraction system (XRD), scanning electron microscopy (SEM),
and electrical measurement system (Radiant Precision LC 10), respectively. The obtained results
point out that the BLT thin film annealed at 725oC is mostly optimum from a viewpoint of film
quality and ferroelectricity. In particular, the optimum BLT thin film having a thickness of 200
nm does not contain any cracks on the sample surface, and the grain size is closed to 400 nm from
SEM observation. XRD patterns imply that the BLT thin film had stoichiometric structure with
preferred orientations of (117) and (006), when annealed at temperatures higher than 725oC. In
addition, we found the influence of La (0.75) dopping on c-axis-oriented growth of BLT thin
films is clear from the structural analysis. The remanent polarization of optimum BLT thin film is
approximately 10 µC/cm2, but the ferroelectric hysteresis loops are not saturated at low applied
voltages.Van Dung TranHa HoangThi Thanh Tam HoangThi Dung VuVan Dung NguyenHong Minh DoThi Huyen Trang VuQuang Hoa NguyenNguyen Quoc Trinh Buitrinhbnq@vnu.edu.vn