Sang‐Hee Ko Park 교수

Recently, hafnia ferroelectrics with two spontaneous polarization states have attracted marked attention for non-volatile, super-steep switching devices, and neuromorphic application due to their fast switching, scalability, and CMOS compatibility. However, field cycling-induced instabilities are a serious obstacle in the practical application of various low-power electronic devices that require a settled characteristic of polarization hysteresis. In this work, a large reduction in the field cyc

Fabrication of barrier layers on a PES film and an organic light emitting diode (OLED) based on a glass substrate by atomic layer deposition (ALD) have been carried out. Deposition of 30 nm of film on both sides of PES film at 90°C gave film MOCON value of The passivation performance of the double layer consisting of deposited by plasma-enhanced chemical vapor deposition and by ALD on the OLED has been investigated using the OLED based on a glass substrate. Preliminary life time of two pairs of

Flexible transparent display is a promising candidate to visually communicate with each other in the future Internet of Things era. The flexible oxide thin‐film transistors (TFTs) have attracted attention as a component for transparent display by its high performance and high transparency. The critical issue of flexible oxide TFTs for practical display applications, however, is the realization on transparent and flexible substrate without any damage and characteristic degradation. Here, the ultr

Transparent ZnO thin film transistor (TFT) array of 176 x 144 (106 dpi) was fabricated on glass substrate. The V-th of the TFT with inverted coplanar structure is about 0.8 V and the mobility is 1.13 cm(2)/V s. The active layer (ZnO), gate insulator (Al2O3), and source-drain electrode (ZnO:Al) were deposited by atomic layer deposition. We also compared the performance of TFTs fabricated by lift-off and wet-etching process as the patterning processes of ZnO layer. The carrier density of the ZnO l

We fabricated amorphous InGaZnO thin film transistors (a-IGZO TFTs) with aluminum oxide (Al₂O₃) as a gate insulator grown through atomic layer deposition (ALD) method at different deposition temperatures (<i>T</i> _dep). The Al₂O₃ gate insulator with a low <i>T</i> _dep exhibited a high amount of hydrogen in the film, and the relationship between the hydrogen content and the electrical properties of the TFTs was investigated. The de

Highly sensitive and flexible pressure sensors were developed based on dielectric membranes composed of insulating microbeads contained within polyvinylidene fluoride (PVDF) nanofibers. The membrane is fabricated using a simple electrospinning process. The presence of the microbeads enhances porosity, which in turn enhances the sensitivity (1.12 kPa^-1 for the range of 0-1 kPa) of the membrane when used as a pressure sensor. The microbeads are fixed in position and uniformly distribute

Abstract A memristive nonvolatile logic‐in‐memory circuit can provide a novel energy‐efficient computing architecture for battery‐powered flexible electronics. However, the cell‐to‐cell interference existing in the memristor crossbar array impedes both the reading process and parallel computing. Here, it is demonstrated that integration of an amorphous In‐Zn‐Sn‐O (a‐IZTO) semiconductor‐based selector (1S) device and a poly(1,3,5‐trivinyl‐1,3,5‐trimethyl cyclotrisiloxane) (pV3D3)‐based memristor

Zinc oxide films were grown in a temperature range of by plasma-enhanced ALD for the application of flexible transparent thin-film transistor (TFT). We have investigated the effect of precursor pulsing time, temperature, and radio frequency power on the film growth. The X-ray diffraction patterns of polycrystalline ZnO films showed rather preferred (002) orientation even at a low temperature of . We could obtain highly resistant ZnO film, being suitable for the active layer of TFT, at low temper

Transparent conductive, Al-doped ZnO films (ZnO:Al) have been deposited by means of an atomic layer deposition method with the surface chemical compositions of ZnO (film A) and Al 2 O 3 (film B). The sheet resistance, surface work function, and structure characteristics of ZnO:Al films have been investigated. Organic light emitting diodes (OLEDs) were fabricated on glass substrates using two different ZnO:Al anodes. The devices fabricated with them exhibited higher current and luminance with hig

This study proposes double oxide semiconductors as a strategy for human-brain like energy consuming synaptic transistor. IZO/IGZO synaptic transistor consumed a minimum energy of 0.269 fJ, and successfully mimicked various synaptic plasticity.

Abstract We have fabricated 2.5″ QCIF + bottom emission AM‐OLED with aperture ratio of 59.6% using fully transparent ZnO‐TFT array and highly conductive oxide/metal/oxide electrode for the first time. The bias stability of ZnO TFT was improved by optimizing ZnO deposition and first gate insulator process. Plasma free process for the gate insulator makes ZnO TFT very stable under electrical bias stress. The Vth shift was less than 0.3V after V DS =25 V and V GS =15 V application for 60 hours. Tra