Low-voltage field emission from tungsten fiber arrays in a stabilized zirconia matrix

1987 ◽  
Vol 2 (3) ◽  
pp. 322-328 ◽  
Author(s):  
J. K. Cochran ◽  
A. T. Chapman ◽  
D. N. Hill ◽  
K. J. Lee

Field emitter array cathodes were fabricated from unidirectionally solidified composites of tungsten fibers in an insulating yttria-stabilized-zirconia (YSZ) matrix. A close-spaced molybdenum gate film (extractor) was formed utilizing c-beam evaporation of alumina as an insulator, which was overlayed by the molybdenum extractor. The high resistivity of the composite matrix coupled with the alumina insulator resulted in low leakage current and permitted dc operation of the device. Emission testing demonstrated current densities of 1–5 A/cm2 with leakage in the μA range for applied potentials of 125–200 V. Variation of emitter tip geometries from hemispheres to right circular cylinders to pointed cones produced increases in emission consistent with reduced tip radii.

1999 ◽  
Vol 14 (11) ◽  
pp. 4395-4401 ◽  
Author(s):  
Seung-Hyun Kim ◽  
D. J. Kim ◽  
K. M. Lee ◽  
M. Park ◽  
A. I. Kingon ◽  
...  

Ferroelectric SrBi2Ta2O9 (SBT) thin films on Pt/ZrO2/SiO2/Si were successfully prepared by using an alkanolamine-modified chemical solution deposition method. It was observed that alkanolamine provided stability to the SBT solution by retarding the hydrolysis and condensation rates. The crystallinity and the microstructure of the SBT thin films improved with increasing annealing temperature and were strongly correlated with the ferroelectric properties of the SBT thin films. The films annealed at 800 °C exhibited low leakage current density, low voltage saturation, high remanent polarization, and good fatigue characteristics at least up to 1010 switching cycles, indicating favorable behavior for memory applications.


2000 ◽  
Vol 622 ◽  
Author(s):  
Margarita P. Thompson ◽  
Gregory W. Auner ◽  
Changhe Huang ◽  
James N. Hilfiker

ABSTRACTAlN films with thicknesses from 53 to 79 nm were deposited on 6H-SiC substrates via Plasma Source Molecular Beam Epitaxy (PSMBE). The influence of deposition temperature on the growth mode and film roughness was assessed. The optical constants of the films in the range 0.73-8.75 eV were determined using spectroscopic ellipsometry. Pt/AlN/6H-SiC MIS structures were created and current-voltage (I-V) and capacitance-voltage (C-V) measurements were performed at room temperature and at 250°C. Most of the MIS structures showed rectifying I-V characteristics regardless of growth temperature. A 120-nm-thick AlN film was deposited at 500°C. MIS structures created on this film showed a very low leakage current densities of 6×10−8 A/cm2. The dielectric constant of the film was estimated at approximately 9. The relation between film structure and electrical properties of the films is discussed.


1982 ◽  
Vol 16 ◽  
Author(s):  
A. Musa ◽  
J.P. Ponpon ◽  
M. Hage-Ali

ABSTRACTOhmic and rectifying contacts on high resistivity etched P-type cadmium telluride have been studied in order to produce diode structures.For this,we have first investigated the properties of gold contacts obtained by chemical reactions of CdTe dippedin gold chloride.Both electrical characterization and structure have been analyzed as a function of the experimental conditions of the contact deposition.The results can be interpreted in terms of a current flow enhanced by tunnelling through the Au-CdTe junction and related to the structure of the interface a few tens of nanometer below the gold contact. In addition,several rectifying contacts have been investigated , in order to achieve a structure having low leakage current.


2017 ◽  
Vol 897 ◽  
pp. 63-66
Author(s):  
Selsabil Sejil ◽  
Loic Lalouat ◽  
Mihai Lazar ◽  
Davy Carole ◽  
Christian Brylinski ◽  
...  

This study deals with the electrical characterization of PiN diodes fabricated on a 4°off-axis 4H-SiC n+ substrate with a n- epilayer (1×1016 cm-3 / 10 µm). Optimized p++ epitaxial areas were grown by Vapour-Liquid-Solid (VLS) transport to form p+ emitters localized in etched wells with 1 µm depth. Incorporated Al level in the VLS p++ zones was checked by SIMS (Secondary Ion Mass Spectroscopy), and the doping level was found in the range of 1-3×1020 at.cm-3. Electrical characterizations were performed on these PiN diodes, with 800 nm deposit of aluminium as ohmic contact on p-type SiC. Electrical measurements show a bipolar behaviour, and very high sustainable forward current densities ≥ 3 kA.cm-2, preserving a low leakage current density in reverse bias. These measurements were obtained on structures without any passivation and no edge termination.


2021 ◽  
Vol 21 (9) ◽  
pp. 4694-4699
Author(s):  
Byung-Yoon Park ◽  
Sungho Choi ◽  
Taek Ahn

The relationships between the microstructure and the dielectric properties of sol–gel prepared Y2O3 films with various Gd3+ doping were systematically investigated. Robust solution processed lanthanide films, (Y1−xGdx)2O3 (0 < x ≤ 0.5), are demonstrated as high-k gate insulators for low voltage-driven oxide thin film transistors and their optimized composition is presented. With the proper amount of Gd3+ doping, the corresponding thin film insulators exhibit low leakage current with increased dielectric constant. The resultant Zn–Sn–O/(Y, Gd)2O3 TFT exhibits enhanced performance, by a factor of 10.7 compared with TFTs using a SiO2 insulator, with a field-effect mobility of ~3.15 cm2V−1s−1 and an exceptionally low operating voltage <15 V.


2001 ◽  
Vol 16 (10) ◽  
pp. 3005-3008 ◽  
Author(s):  
F. Ayguavives ◽  
B. Agius ◽  
B. EaKim ◽  
I. Vickridge

Lead zirconate titanate (PZT) thin films were deposited in a reactive argon/oxygen gas mixture by radio-frequency-magnetron sputtering. The use of a metallic target allows us to control the oxygen incorporation in the PZT thin film and also, using oxygen 18 as a tracer, to study the oxygen diffusion in the thin films. Electrical properties and crystallization were optimized with a 90-nm PZT thin film grown on RuO2 electrodes. These PZT films, annealed with a very modest thermal budget (550 °C) show very low leakage current densities (J = 2 × 10−8 A/cm2 at 1 V). In this article we show that a strong correlation exists between the oxygen composition in the PZT film and the leakage current density.


2006 ◽  
Vol 89 (20) ◽  
pp. 202908 ◽  
Author(s):  
Mi-Hwa Lim ◽  
KyongTae Kang ◽  
Ho-Gi Kim ◽  
Il-Doo Kim ◽  
YongWoo Choi ◽  
...  

1998 ◽  
Vol 535 ◽  
Author(s):  
M. Hong ◽  
J. Kwo ◽  
A. R. Kortan ◽  
J. P. Mannaerts ◽  
M. C. Wu ◽  
...  

AbstractSingle crystal Gd2O3 dielectric thin films were epitaxially grown on GaAs. The Gd2O3 film has a cubic structure isomorphic to Mn2O3, and is (110) oriented in single domain on the (100) GaAs surface. The oxide film has low leakage current densities ˜ 10–9 – 10–10 A/cmT2 at zero bias. Typical breakdown field is 4 MV/cm for an oxide film 185 Å thick, and >10 MV/cm for an oxide less than 50 Å thick. Both accumulation and inversion layers were observed in the Gd2O3-GaAs metal oxide semiconductor (MOS) diodes using capacitance-voltage (C-V) measurements, with an interfacial density of states around 1011 cm–2 eV–1.


2021 ◽  
Vol 16 (1) ◽  
pp. 1-7
Author(s):  
Shaifudin Muhamad Syaizwadi ◽  
Mohd Sabri Mohd Ghazali ◽  
Wan Mohamad Kamaruzzaman Wan Mohamad Ikhmal ◽  
Mohd Anuar Muhamad Syahmi Hazim ◽  
Wan Abdullah Wan Rafizah ◽  
...  

Application of ZnO varistor at low voltage has increased significantly due to the high demands of low-voltage electronics with high nonlinearity characteristics and low leakage current. The varistor ceramics were developed via solid-state reaction method and the resultant sample was analyzed by means of SEM, EDS and XRD. The nonlinearity characteristics of ZnO varistor ceramics for different contents of cobalt oxide (Co3O4) at a given barium titanate (BaTiO3) amount were analyzed based on the J-E characteristics measurement. The increased value of nonlinear coefficient (α) equal to 4.8 was exhibited by the sample made with 12 wt.% BaTiO3 additive. As the concentration of dopant (Co3O4) incorporated was increased from 0.5 to 1.5 wt.%, the varistor voltage limit decreased from 8.9 V/mm to 7.0 V/mm, respectively. Additionally, the barrier height increased from 0.88 to 0.98 eV for 0.0 wt.% to 1.0 wt.% of Co3O4 concentration, respectively. The highest α of 7.2 was obtained at 0.5 wt.% Co3O4 and decreased with further doping content due to to the reduction of barrier height caused by the variation of electronic state at the grain boundaries.


2014 ◽  
Vol 1635 ◽  
pp. 75-81
Author(s):  
Anders Olsson ◽  
Abuduwayiti Aierken ◽  
Jani Oksanen ◽  
Harri Lipsanen ◽  
Jukka Tulkki

ABSTRACTLight-emitting diodes (LEDs) based on the conventional III-V compound semiconductors are known to exhibit internal quantum efficiencies (IQE) that are very close to unity. Ideally, the high IQE is expected to enable electroluminescent cooling with a cooling capacity of several Watts per cm2 of emitter area. One key requirement in enabling such cooling is the ability to fabricate high quality large area LEDs. However, detailed information on the performance of relevant large area devices and their yield is extremely scarce. In this report we present data on the yield and related large area scaling of InP/InGaAs LEDs by using current-voltage measurements performed on LED wafers fabricated at five different facilities. The samples were processed to contain square shaped mesas of sizes 0.25 mm2 and 16 mm2 operating as LEDs. While most of the smaller mesas showed relatively good electrical characteristics and low leakage current densities, some of them also exhibited very large leakage currents. In addition, in some cases the large area devices exhibited large, and even almost linearly behaving leakage currents. Such information on the scaling and unidealities of diodes fabricated using established fabrication technologies is crucial for the development of the optical cooling technologies relying on large area devices.


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