• Transactions on Electrical and Electronic Materials
• /
• v.17 no.2
• /
• pp.104-108
• /
• 2016

To research the correlation between oxygen vacancy and the electrical characteristics of ZTO, which is made by using a target mixed ZnO:SnO₂=1:1, the ZnO, SnO₂ and ZTO were analyzed by PL, XPS, XRD patterns and electrical properties. It was compared with the electron orbital spectra of O 1s in accordance with the electrical characteristics of ZnO, SnO₂ and ZTO. The electrical characteristics of ZTO were improved by increasing the annealing temperatures, due to the high degree of crystal structures at a high temperature, and the physical properties of ZTO was similar to that of ZnO. The amorphous structure of SnO₂ was increased with increasing the temperature. The Schottky contact of oxide semiconductors was formed using the depletion region, which is increased by the electron-hole combination due to the annealing processes. ZnO showed the Ohmic contact in spite of a high annealing temperature, but SnO₂ and ZTO had Schottky contact. As such, it was confirmed that the electrical properties of ZTO are affected by the molecules of SnO₂.

• Electrical & Electronic Materials
• /
• v.10 no.2
• /
• pp.97-104
• /
• 1997

In this paper, in order to investigate the behavior of charged particles on (Sr.Ca)TiO$_{3}$ ceramics with paraelectric properties, the characteristics of electrical conduction and thermally stimulated current was measured respectively. As a result, the conduction mechanism is divided into three regions having different mechanism as the current increased. The region I below 200[V/Cm] shows the ohmic conduction. The region B between 200[V/cm] and 2000[V/cm] can be explained by the Poole-Frenkel emission theory, and the region III above 2000[V/cm] is dominated by the tunneling effect. The three peaks of TSC were obtained at the temperature of -20[.deg. C], 20[.deg. C] and 80[.deg. C], respectively. The origins of these peaks are that the .alpha. peak observed at -20[.deg. C] looks like to be ascribed to the ionization excitation from donor level in the grain, and the .alpha.' peak observed at 20 [.deg. C] appears to show up by hopping conduction of the trapped carrier of border between the oxidation layer and the grain, and the .betha. peak observed at 80[.deg. C] seems to be resulted from hopping conduction of existing carrier in the trap site of the border between the oxidation and second phase.

• Electrical & Electronic Materials
• /
• v.8 no.5
• /
• pp.611-618
• /
• 1995

The (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.6[mol%]Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramics were fabricated to form semiconducting ceramics by sintering at about 1350[.deg. C] in a reducing atmosphere(N$_{2}$ gas). Metal oxides, CuO, was painted on the both surface of the specimens to diffuse to the grain boundary. They were annealed at 1100 [.deg. C] for 2 hours. The 2nd phase formed by thermal diffusing from the surface lead to a very high apparent dielectric constant. According to increase of the frequency as a functional of temperature, all specimens used in this study showed the dielectric relaxation, and the relaxation frequency was above 106 [Hz], it move to low frequency with increasing resistivity of grain. The specimens showed three kinds of conduction mechanisms in the temperature range 25-125 [.deg. C] as the current increased: the region I below 200 [V/cm] shows the ohmic conduction. The region rt between 200 [V/cm] and 2000 [V/cm] can be explained by the Poole-Frenkel emission theory, and the region III above 2000 [V/cm] is dominated by the tunneling effect.fect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.11a
• /
• pp.209-212
• /
• 1995

In this paper, the $(Sr_{0.85}{\cdot}Ca_{0.15})TiO_3$ of paraelectric grain boundary layer (GBL) ceramics were fabricated. The characteristics of electrical conduction and the thermally stimulated current(TSC) were measured respectively. The region I below 200[V/cm] shows the ohmic conduction, the region II between 200[V/cm] and 1000[V/cm] can be explained by the Pool-Frenkel emission theory, and the region III above 2000[V/cm] is dominated by the tunneling effect. As a result, The origins of these peaks are that the ${\alpha}$ peak observed at $-20[^{\circ}C]$ looks like to be ascribed to the ionization excitation from donor level in the grain, and the ${\alpha}^{\prime}$ peak observed at $-20[^{\circ}C]$ appears to show up by detrap of the trapped carrier of border between the oxidation layer and the grain, and the ${\beta}$ peak observed at $80[^{\circ}C]$ seems to be resulted from hopping conduction of existing carrier in the trap site of the border between the oxidation and second phase.

• Electrical & Electronic Materials
• /
• v.8 no.5
• /
• pp.619-625
• /
• 1995

Polycrystalline CdTe thin film has been studied for photovoltaic application due to the 1.45 eV band gap energy ideal for solar energy conversion and high absorption coefficient. The formation of low resistance contact to p-CdTe is difficult because of large work function(>5.5eV). Common methods for ohmic contact to p-CdTe are to form a p+ region under the contact by in-diffusion of contact material to reduce the barrier height and modify a p-CdTe surface layer using chemical treatment. In this study, the surface chemical treatment of p CdTe was carried out by H$\_$3/PO$\_$4/+HNO$\_$3/ or K$\_$2/Cr$\_$2/O$\_$7/+H$\_$2/SO$\_$4/ solution to provide a Te-rich surface. And various thin film contact materials such as Cu, Au, and Cu/Au were deposited by E-beam evaporation to form ohmic contact to p-CdTe. After the metallization, post annealing was performed by oven heat treatment at 150.deg. C or by RTA(Rapid Thermal Annealing) at 250-350.deg. C. Surface chemical treatments of p-CdTe thin film improved metal/p-CdTe interface properties and post heat treatment resulted in low contact resistivity to p-CdTe.Of the various contact metal, Cu/Au and Cu show low contact resistance after oven and RTA post-heat treatments, respectively.

• Journal of the Korean Applied Science and Technology
• /
• v.23 no.3
• /
• pp.238-242
• /
• 2006

Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electric conduction mechanism of PI Ultra-Thin Films was investigated at room temperature. At low electric field, ohmic conduction $(I{\propto}V)$ was observed and the calculated electrical conductivity was about $4.23{\times}10^{-15}{\sim}9.81{\times}10^{-15}\;S/cm$. At high electric field, nonohmic conduction $(I{\propto}V^2)$ was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of PI Ultra-Thin Films was about 7.0.

• Journal of Advanced Marine Engineering and Technology
• /
• v.27 no.1
• /
• pp.33-41
• /
• 2003

The optical properties of $ZnS_ySe_{1-\chi-y}:Te_{\chi}(\chi<0.08,y~0.11)$ alloys grown by molecular beam epitaxy (MBE) have been investigated by photoluminescence (PL) and PL-excitation (PLE) spectroscopy. Good optical properties and high crystal quality were established with lattice match condition to GaAs substrate. At room temperature, emission in the visible spectrum region from blue to green was obtained by varying the Te content of the ZnSSe:Te alloy. The efficient blue and green emission were assigned to $Te_1 and Te_n(n\geq2)$cluster bound excitons, respectively. Bright green (535 nm) and blue (462 nm) light emitting diodes (LEDs) have been developed using ZnSSe:Te system as an active layer. The turn-on voltage of 2.1 V in current-voltage characteristics is very small compared to that of commercial InGaN-based LEDs (>3.4 V), indicating the formation of a good ohmic contact due to the optimized p-ZnSe/p-ZnTe multi-quantum well (MQW) superlattice electrode layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1988.10a
• /
• pp.33-35
• /
• 1988

From the study of mechanism of electrical conduction of film which is made from Polyethylene Terephthalate at very high temperature which is larger than low electric field and glass transition point, we find that there is a extraordinary non ohmic region (I∝V$^n$, 0

• Transactions on Electrical and Electronic Materials
• /
• v.5 no.1
• /
• pp.24-28
• /
• 2004

We have used ITO/Alq$_3$/Al structure to study electrical conduction mechanism in organic light-emitting diodes. Current-voltage-luminance characteristics were measured at room temperature by varying the thickness of Alq$_3$ layer from 60 to 400mm. We were able to confirm that there are three different mechanisms depending on the applied voltage region; ohmic, space-charge-limited current, and trap-charge-limit-current mechanism. And the maximum luminous efficiency was obtained when the thickness of Alq$_3$ layer is 200nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.480-483
• /
• 2000

Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electrical properties of PI LB films were investigated at room temperature. At low electric field, ohmic conduction(I∝V) was observed and the calculated electrical conductivity was about 9.7$\times$10$^{-15}$ S/cm. At high electric field, conduction(I∝V$^2$) was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of LB film was about 7.5.