• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.972-974
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• 2005

For display drivers employ typically a-Si n-channel field effect transistors, they require an inverted OLED structure with a cathode as the bottom contact. ITO is regarded as the bottom cathode and can be applied to large size AM-OLED and transparent inverted OLEDs. We report the effective structure to improve the efficiency of electron injection from ITO cathode to $Alq_3$. We report the effective structure to improve the efficiency of electron injection from ITO cathode to Alq3 and studied the current density-voltage characteristics of trilayer ($Alq_3-LiF-Al$), LiF and Mg inserted between ITO and $Alq_3$, respectively. We discovered that 1 nm Mg afforded the highest efficiency.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.79-87
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• 1998

Nitrided oxides which have been investigated as alternative gate oxide for metal-oxide-semiconductor field effect devices were grown by two-step process using N$_{2}$O gas, and were chaacterized via a fowler-nordheim tunneling(FNT) electron injection technique. Electrical characteristics of nitrided gate oxides were superior to that of control oxides.Further, the FNT electron injection into the nitrided gate oxides reveals that gate oxides degrade more both if electrons were foreced to inject from the gate metal and if thicker nitrided gate oxides were used in the thickness range of 90~130.angs.. Models are suggested to explain these phenomena.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.3
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• pp.100-109
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• 1995

A new Hydrodynamic model for the high energy tail electrons(Tail Electron Hydrodynamic Model : TEHD) is developed using the moment method. The Monte Carlo method is applied to a $n^{+}-n^{-}-n^{+}$ device to calibrate the TEHD equations. the discretization method and numerical procedures are explained. New models for the impact ionization and injection into the gate oxide using the tail electron density are proposed. The simulated results of the impact ionization rate for a $n^{+}-n^{-}-n^{+}$ device and MOSFET devices, and the gate injection experiment are shown to give good agreement with the Monte Carlo simulation and the measurements.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.706-709
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• 2002

We investigated the effect of lithium 8-hydroxyquinolinolatolithium (Liq) as an electron injection layer on the performance of organic light emitting devices (OLEDs) and optimized the device efficiency by varying thickness of Liq layer. The device with 1nm Liq layer showed significant enhancement of the device performance and device lifetime. We also compared $Znq_2$ and LiBBOX with Liq as an electron injection layer.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.77-87
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• 1993

PMOSFETs were studied on the effect of Hot-Carrier induced drain leakage current (Gate-Induced-Drain-Leakage). The result turned out that change in Vgl(drain voltage where 1pA/$\mu$m of drain leadage current flows) was largest in the Channel-Hot-Hole(CHH) injection condition and next was in dynamic stress and was smallest in electron trapping (Igmax) condition under various stress conditions. It was analyzed that if electron trapping occurrs in the overlap region of gate and drain(G/D), it reduces GIDL current due to increment of flat-band voltage(Vfb) and if CHH is injected, interface states(Nit) were generated and it increases GIDL current due to band-to-defect-tunneling(BTDT). Especially, under dynamic stress it was confirmed that increase in GIDL current will be high when electron injection was small and CHH injection was large. Therefore as applying to real circuit, low drain voltage GIDL(BTDT) was enhaced as large as CHH Region under various operating voltage, and it will affect the reliablity of the circuit.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.1023-1026
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• 2007

Highly efficient inverted bottom emission organic light emitting device (IBOLED) with a structure of ITO/EIL/Alq3/NPB/WO3/Al was investigated. To enhance electron injection from ITO cathode to Alq3 EML layer, we introduced ultra thin Al layer and Liq layer between ITO and Alq3. The device characteristics showed tune on voltage of 4.5V, the maximum luminance of 21100 Cd/m2 and current efficiencies of 3.56 Cd/A.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4063-4068
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• 2012

Oxide substrates in semiconductor-sensitized solar cells (SSSCs) have a great impact on their performance. $TiO_2$ has long been utilized as an oxide substrate, and other alternatives such as ZnO and $SnO_2$ have also been explored due to their superior physical properties over $TiO_2$. In the development of high-performance SSSCs, it is of significant importance to understand the effect of oxides on the electron injection and charge recombination as these two are major factors in dictating solar cell performance. In addition, elucidating the relationship between these two critical processes and solar cell performance in each oxide is critical in building up the basic foundation of SSSCs. In this study, ultrafast pump-probe laser spectroscopy and open-circuit decay analysis were conducted to examine the characteristics of three representative oxides ($TiO_2$, ZnO, and $SnO_2$) in terms of electron injection kinetics and charge recombination, and the implication of results is discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.475-476
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• 2005

Efficient electron injection is essential to achieve bright and efficient organic light-emitting diodes (OLEDs). In spite of high work function of Al, it is a common cathode because of its stability. In this paper, to overcome the poor electron injection in OLEDs with Al cathode, OLEDs with various composite cathodes were fabricated and investigated using a conventional OLEDs structure of indium tin oxide ITO/NPB(40 nm)/$Alq_3$(50 nm)/Al. composite cathodes were composed of alkaline materials such as Ca and Li, Al deposition or codeposited with AI. We showed best performance at the device with composite cathode (LiF/Al).

• Journal of Electrochemical Science and Technology
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• v.13 no.1
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• pp.100-111
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• 2022

This paper presents a simple and inexpensive method to fabricate chemically and mechanically resistant hot electron-emitting composite electrodes on reusable substrates. In this study, the hot electron emitting composite electrodes were manufactured by doping a polymer, nylon 6,6, with few different brands of carbon particles (graphite, carbon black) and by coating metal substrates with the aforementioned composite ink layers with different carbon-polymer mass fractions. The optimal mass fractions in these composite layers allowed to fabricate composite electrodes that can inject hot electrons into aqueous electrolyte solutions and clearly generate hot electron- induced electrochemiluminescence (HECL). An aromatic terbium (III) chelate was used as a probe that is known not to be excited on the basis of traditional electrochemistry but to be efficiently electrically excited in the presence of hydrated electrons and during injection of hot electrons into aqueous solution. Thus, the presence of hot, pre-hydrated or hydrated electrons at the close vicinity of the composite electrode surface were monitored by HECL. The study shows that the extreme pH conditions could not damage the present composite electrodes. These low-cost, simplified and robust composite electrodes thus demonstrate that they can be used in HECL bioaffinity assays and other applications of hot electron electrochemistry.

• Transactions on Electrical and Electronic Materials
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• v.13 no.2
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• pp.60-63
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• 2012

Enhancement of efficiency and luminance of organic light-emitting diodes was investigated by the introduction of a lithium carbonate ($Li_2CO_3$) electron-injection layer. Electron-injection layer is used in organic light-emitting diodes to inject electrons efficiently between a cathode and an organic layer. A device structure of ITO/TPD (40 nm)/$Alq_3$ (60 nm)/$Li_2CO_3$ (x nm)/Al (100 nm) was manufactured by thermal evaporation, where the thickness of $Li_2CO_3$ layer was varied from 0 to 3.3 nm. Current density-luminance-voltage characteristics of the device were measured and analyzed. When the thickness of $Li_2CO_3$ layer is 0.7 nm, the current efficiency and luminance of the device at 8.0 V are improved by a factor of about 18 and 3,000 compared to the ones without the $Li_2CO_3$ layer, respectively. The enhancement of efficiency and luminance of the device with an insertion of $Li_2CO_3$ electron-injection layer is thought to be due to the lowering of an electron barrier height at the interface region between the cathode and the emissive layer. This is judged from an analysis of current density-voltage characteristics with a Fowler-Nordheim tunneling conduction mechanism model. In a study of lifetime of the device that depends on the thickness of $Li_2CO_3$ layer, the optimum thickness of $Li_2CO_3$ layer was obtained to be 1.1 nm. It is thought that an improvement in the lifetime is due to the prevention of moisture and oxygen by $Li_2CO_3$ layer. Thus, from the efficiency and lifetime of the device, we have obtained the optimum thickness of $Li_2CO_3$ layer to be about 1.0 nm.