Schottky Diodes (schottky + diode)

Distribution by Scientific Domains


Selected Abstracts


Heterointegration of Pt/Si/Ag Nanowire Photodiodes and Their Photocatalytic Properties

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2010
Yongquan Qu
Abstract Photocatalyst mediated photoelectrochemical processes can make use of the photogenerated electrons and holes onsite for photocatalytic redox reactions, and enable the harness and conversion of solar energy into chemical energy, in analogy to natural photosynthesis. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here, it is shown that a Pt/Si/Ag nanowire heterostructure can be rationally synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. The synthesis of Pt/Si/Ag nanowire diodes involves a scalable process including the formation of silicon nanowire array through wet chemical etching, electrodeposition of platinum and photoreduction of silver. The Pt/Si/Ag diodes exhibit highly efficient photocatalytic activity for a wide range of applications including environmental remediation and solar fuel production in the visible range. In this article, photodegradation of indigo carmine and 4-nitrophenol are used to evaluate the photoactivity of Pt/Si/Ag diodes. The Pt/Si/Ag diodes also show high activity for photoconversion of formic acid into carbon dioxide and hydrogen. [source]


Heterointegration of Pt/Si/Ag Nanowire Photodiodes and Their Photocatalytic Properties

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2010
Yongquan Qu
Abstract Photocatalyst mediated photoelectrochemical processes can make use of the photogenerated electrons and holes onsite for photocatalytic redox reactions, and enable the harness and conversion of solar energy into chemical energy, in analogy to natural photosynthesis. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here, it is shown that a Pt/Si/Ag nanowire heterostructure can be rationally synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. The synthesis of Pt/Si/Ag nanowire diodes involves a scalable process including the formation of silicon nanowire array through wet chemical etching, electrodeposition of platinum and photoreduction of silver. The Pt/Si/Ag diodes exhibit highly efficient photocatalytic activity for a wide range of applications including environmental remediation and solar fuel production in the visible range. In this article, photodegradation of indigo carmine and 4-nitrophenol are used to evaluate the photoactivity of Pt/Si/Ag diodes. The Pt/Si/Ag diodes also show high activity for photoconversion of formic acid into carbon dioxide and hydrogen. [source]


Rewritable Switching of One Diode,One Resistor Nonvolatile Organic Memory Devices

ADVANCED MATERIALS, Issue 11 2010
Byungjin Cho
One diode,one resistor (1D,1R) hybrid-type devices consisting of an inorganic Schottky diode and an organic unipolar memory show electrically rewritable switching characteristics as well as rectifying properties. The 1D,1R array architecture improves the sensing efficiency of the array memory cell, ultimately creating the possibility for high-density integrated organic memory devices without restrictions due to cross-talk between cells. [source]


Ultrawideband monocycle pulse generator with dual resistive loaded shunt stubs

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2007
Tzyh-Ghuang Ma
Abstract An ultrawideband (UWB) monocycle pulse generator with dual resistive loaded shunt stubs is present in this article. The proposed pulse generator consists of a step recovery diode (SRD), a Schottky diode, a pair of resistive loaded stubs, and a pair of short-circuited stubs. By introducing an additional resistive loaded stub between the SRD and the Schottky diode, the ringing tail of the impulse waveform can be substantially suppressed and the resultant monocycle pulse is well-behaved with very low ringing level. The measurement result demonstrates a monocycle pulse with peak-to-peak amplitude of 550 mV, pulsewidth of 320 ps, ringing level of as low as ,22 dB, and good pulse symmetry. This pulse generator is suitable for various UWB applications. 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 459,462, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22145 [source]


High-temperature stability of Au/p-type diamond Schottky diode

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 6 2009
Tokuyuki Teraji
Abstract Rectification properties of Au Schottky diodes were investigated in high-temperature operation. These diodes were fabricated on a p-type diamond single crystal using the vacuum-ultraviolet light/ozone treatment. The ideality factor n of the Schottky diodes decreased monotonically with increasing measurement temperature whereas the Schottky barrier height ,b increased, and ,b reached 2.6 eV at 550 K with n of 1.1. Through high temperature heating at 870 K, the mean value of ,b at 300 K changed permanently from 2.2 eV to 1.1 eV. Decrease of ,b might originate from a dissolution of oxygen termination at the Au/diamond interface. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Current-transport studies and trap extraction of hydrothermally grown ZnO nanotubes using gold Schottky diode

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010
G. Amin
Abstract High-quality zinc oxide (ZnO) nanotubes (NTs) were grown by the hydrothermal technique on n-Si substrate. The room temperature (RT) current-transport mechanisms of Au Schottky diodes fabricated from ZnO NTs and nanorods (NRs) reference samples have been studied and compared. The tunneling mechanisms via deep-level states was found to be the main conduction process at low applied voltage but at the trap-filled limit voltage (VTFL) all traps were filled and the space-charge-limited current conduction was the dominating current-transport mechanism. The deep-level trap energy and the trap concentration for the NTs were obtained as ,0.27,eV and 2.1,,1016,cm,3, respectively. The same parameters were also extracted for the ZnO NRs. The deep-level states observed crossponds to zinc interstitials (Zni), which are responsible for the violet emission. [source]


Effect of rapid thermal annealing on the electrical and structural properties of Ru/n-InP (100) Schottky rectifiers

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2009
V. Janardhanam
Abstract The effects of rapid thermal annealing on the electrical and structural properties of Ru/n-InP Schottky diode have been investigated by current,voltage (I,V), capacitance,voltage (C,V), X-ray diffraction (XRD) and secondary ion-mass spectroscopy (SIMS) techniques. Results showed that the Schottky barrier height of the as-deposited Ru/n-InP has been found to be 0.53,eV (I,V) and 0.69,eV (C,V). The Schottky barrier height increased to 0.54,eV (I,V) 0.73,eV (C,V), 0.56,eV (I,V) and 0.78,eV (C,V) after annealing at 300 and 400,C for 1,min in nitrogen ambient. Further increase in the annealing temperature up to 500,C resulted in the increase of barrier height to 0.57,eV (I,V) and 0.80,eV (C,V). However, after annealing at temperature 600,C, the barrier height decreases to 0.51,eV (I,V) and 0.67,eV (C,V). Based on the results of XRD and SIMS studies, the formation of indium phases at Ru/n-InP interface could be the reason for the increase of barrier height upon annealing at 500,C. The atomic force microscopy results showed that the surface morphology of the contact annealed at 600,C is fairly smooth with a root mean square roughness of 1.8,nm. [source]


High resolution Laplace deep level transient spectroscopy of p-type polycrystalline diamond

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2008
N. Mitromara
Abstract High resolution Laplace deep level transient spectroscopy (LDLTS) has been used to characterise deep electronic states in the band gap of polycrystalline p-type diamond. The thin diamond films were grown by the hot-filament chemical vapour deposition (HFCVD) technique on p-type and n-type Si for the formation of the Schottky and p,n diodes respectively. The B concentration in the diamond films ranged from 7 1018 cm,3 to 7 1021 cm,3. Conventional capacitance DLTS showed a fairly narrow peak at about 180 K from the diamond grown on p-type Si, but further analysis with LDLTS shows that this peak originates from a complex defect with up to three hole emission rates. In the case of the Schottky diode, these emission rates do not vary much with temperature which indicates that they may be due to the presence of an extended defect, where the valence band itself is changing its profile as the traps capture more carriers. LDLTS of a similar trap in the diamond grown on n-type Si also shows three emission rates, which do not vary as expected with temperature. The results are discussed in terms of defects existing in the strain fields of grain boundaries, and exhibiting non point-defect like properties. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Interface properties and junction behavior of Pd contact on ZnO thin film grown by vacuum deposition technique

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2010
Ghusoon M. Ali
Abstract In this paper we explain the results of our experimental investigation on interface properties and junction behavior of Pd contact on ZnO thin film based Schottky diode. We used a conventional vacuum evaporation deposition unit for sequential deposition of ZnO film and metallic layer. For the first time a high quality Pd/ZnO Schottky diode is fabricated successfully in our laboratory by vacuum evaporation method. The I-V and C-V characteristics of the devices were studied by using microprobe arrangement. The parameter such as ideality factor, leakage current, resistance-area-product, carrier concentration and barrier height were extracted from the measured data. The surface morphological and the structural properties of thin film were studied by atomic force microscope. The optical band gap of thin film was determined using UV-visible spectrophotometer. The device fabricated by a simple technique exhibited excellent stability for use as an electronic or optoelectronic component. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Controllable Molecular Doping and Charge Transport in Solution-Processed Polymer Semiconducting Layers

ADVANCED FUNCTIONAL MATERIALS, Issue 12 2009
Yuan Zhang
Abstract Here, controlled p-type doping of poly(2-methoxy-5-(2,-ethylhexyloxy)- p -phenylene vinylene) (MEH-PPV) deposited from solution using tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) as a dopant is presented. By using a co-solvent, aggregation in solution can be prevented and doped films can be deposited. Upon doping the current,voltage characteristics of MEH-PPV-based hole-only devices are increased by several orders of magnitude and a clear Ohmic behavior is observed at low bias. Taking the density dependence of the hole mobility into account the free hole concentration due to doping can be derived. It is found that a molar doping ratio of 1 F4-TCNQ dopant per 600 repeat units of MEH-PPV leads to a free carrier density of 4,,1022,m,3. Neglecting the density-dependent mobility would lead to an overestimation of the free hole density by an order of magnitude. The free hole densities are further confirmed by impedance measurements on Schottky diodes based on F4-TCNQ doped MEH-PPV and a silver electrode. [source]


Organic Base Modulation Triodes and Their Inverters on Flexible Substrates

ADVANCED MATERIALS, Issue 18 2009
Shiau-Shin Cheng
Organic base modulation triodes (OBMTs) are fabricated using two back-to-back Schottky diodes and deposited on a flexible substrate. With the advantage of the shorter channel, the OBMTs can be operated under lower voltages and faster frequencies. The inverter is fabricated using the OBMT connected with a resistor in series. [source]


10W CW broadband balanced limiter/LNA fabricated using MSAG MESFET process

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 2 2003
Inder J. Bahl
Abstract This article presents the design and test data for a 10W broadband balanced limiter/LNA MMIC fabricated using MSAG MESFET process. The limiter is based on Schottky diodes and the two-stage LNA is designed using high-performance MESFETs. The typical measured performance for the limiter/LNA circuit includes gain greater than 14 dB, NF less than 2.7 dB, and return loss better than 20 dB over the 8.5,11.5 GHz frequency range. The CW power handling for the packaged limiter/LNA circuits was greater than 10W. The packaged devices were also exposed to power levels greater than 10W, and no catastrophic failures were observed up to 18W. 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 118,127, 2003. [source]


High-temperature stability of Au/p-type diamond Schottky diode

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 6 2009
Tokuyuki Teraji
Abstract Rectification properties of Au Schottky diodes were investigated in high-temperature operation. These diodes were fabricated on a p-type diamond single crystal using the vacuum-ultraviolet light/ozone treatment. The ideality factor n of the Schottky diodes decreased monotonically with increasing measurement temperature whereas the Schottky barrier height ,b increased, and ,b reached 2.6 eV at 550 K with n of 1.1. Through high temperature heating at 870 K, the mean value of ,b at 300 K changed permanently from 2.2 eV to 1.1 eV. Decrease of ,b might originate from a dissolution of oxygen termination at the Au/diamond interface. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Current-transport studies and trap extraction of hydrothermally grown ZnO nanotubes using gold Schottky diode

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010
G. Amin
Abstract High-quality zinc oxide (ZnO) nanotubes (NTs) were grown by the hydrothermal technique on n-Si substrate. The room temperature (RT) current-transport mechanisms of Au Schottky diodes fabricated from ZnO NTs and nanorods (NRs) reference samples have been studied and compared. The tunneling mechanisms via deep-level states was found to be the main conduction process at low applied voltage but at the trap-filled limit voltage (VTFL) all traps were filled and the space-charge-limited current conduction was the dominating current-transport mechanism. The deep-level trap energy and the trap concentration for the NTs were obtained as ,0.27,eV and 2.1,,1016,cm,3, respectively. The same parameters were also extracted for the ZnO NRs. The deep-level states observed crossponds to zinc interstitials (Zni), which are responsible for the violet emission. [source]


Reliability aspects of SiC Schottky diodes

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2009
Matthias Holz
Abstract In recent years, silicon carbide (SiC) high-voltage power devices have gained an ever-increasing market share. The fast development of new device concepts and technologies, e.g. for SiC Schottky diodes, has led to devices with superior switching behaviour, which renders SiC power devices especially favourable for high-frequency applications. As of today, SiC devices enter various fields like, e.g. server power supplies, solar inverters, and drives. These applications pose quite different requirements not only on the electrical properties, but also on the long-term reliability of the devices. In this paper, we describe in detail how Infineon's SiC Schottky diodes excel the reliability requirements. We point out how material properties, device design and packaging technology affect the overall device reliability and how they can be optimized. In addition, we describe measurement results after stress tests that go far beyond standard stress tests according to JEDEC. E.g., we show that SiC devices can safely be operated at high voltage slopes of 120 V/ns. In addition, we show that the use of high performance die attach further improves the device properties and reliability. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Characterization of deep levels at GaAs/GaAs and GaAs/InAs interfaces grown by MBE-interrupted growth technique

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2007
M. Kaniewska
Abstract In order to find the origin of crystalline defects occurring in the preparation of InAs/GaAs quantum dots (QDs), their appearance was tracked through three different sample types designed as Schottky diodes. Specimens with a GaAs cap layer on a GaAs buffer layer as well as with an InAs wetting layer without QDs were grown by molecular beam epitaxy (MBE) using the interrupted growth technique. Deep level transient spectroscopy (DLTS) was used for comparison with structures containing InAs QDs. It was found that two main levels with thermal activation energies of 0.14,0.16 eV and 0.46,0.52 eV from the conduction band edge, respectively, are grown-in defects, which are characteristic of the growth interrupted interface occuring under an excess of As. Both these levels together with an additional level at 0.10,0.12 eV found in the InAs wetting layer structures were also present in those with QDs, probably resulting from strain or In penetration. All three defects were agglomerated close to the interface created by the interrupted growth. ( 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Anomalous capacitance,voltage characteristics of Pt,AlGaN/GaN Schottky diodes exposed to hydrogen

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010
Yoshihiro Irokawa
Abstract We have investigated the interaction of hydrogen with Pt-AlGaN/GaN Schottky barrier diodes (SBDs) using a low-frequency capacitance-voltage (C-V) technique. At a frequency of 1kHz, the C-V curve in hydrogen shifts toward negative bias values as compared with that in nitrogen. As the frequency decreases from 1kHz to 1Hz, the capacitance in hydrogen significantly increases and the fluctuations of the capacitance are observed. These C-V characteristics are quite anomalous and have not been reported yet, suggesting the formation of interfacial polarization which could be attributable to hydrogen-related dipoles. The fluctuation of the capacitance may be related to the alignment of the dipoles. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Characteristics of He+ -irradiated Ni Schottky diodes based on 4H-SiC epilayer grown by sublimation

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2009
A. M. Strel'chuk
Abstract Forward and reverse current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the of He+ , irradiated Ni-SiC(4H) Schottky diodes (SDs) are presented prior and after irradiation. The effect of irradiation was weakly observed in the region of small forward and reverse current, but series resistance of SD demonstrated tendency to rise with increasing irradiation dose. The most interesting effect was the big scatter of the series resistances after exposure to high irradiation dose 21012 cm -2. By contrast, uncompensated donor concentration had just minor changes (from 3.31017 cm -3 prior irradiation to 1.81017 cm -3 at highest irradiation dose) with no connection with SDs resistance. Hypothesis that localized defect-induced current paths could explain this behaviour is discussed. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Capabilities of CdZnTe-based Schottky diodes for detection of optical and X/,-ray radiation

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2009
O. L. Maslyanchuk
Abstract The electrical and photoelectric properties of Schottky diodes based on low-resistivity (, = 103 -104 ,cm) and semi-insulating (, , 107 ,cm) Cd1-xZnxTe (x = 0-0.2) single crystals are investigated and use of the diodes as detectors, respectively, for optical and X- and ,-ray radiation is analyzed. The charge transport properties of both types of Schottky diodes are shown to be governed by generation-recombination in the space-charge region in the frame of the Sah-Noyce-Shockley theory. The detection spectrum of Cd1,xZnx Te-bassed X/,-ray detectors with Schottky diodes is studied. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Study of the influence of ,-particles irradiation on AlGaAs/GaAs heterojunction structures

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008
P. Georgakakos
Abstract Aim of the present work is to study the influence of the radiation of ,-particles (5 MeV) in Schottky diodes on CaAs/AlGaAs/GaAs heterojunction structures. The investigation was performed by means of current-voltage and capacitance-voltage characteristics in 300 K temperature. The dependence of ideality factor, barrier height, carrier concentration and series resistance as a function of radiation fluence was determined. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


GaN-based Schottky diodes for hydrogen sensing in transformer oil

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
Peter Sandvik
Abstract We report the demonstration of robust, GaN-based hydrogen sensors for use directly in transformer oil. These 1 mm2 Schottky diodes were immersed in a closed loop with Voltesso insulating oil for 21 months of continuous testing. They showed good reproducibility in response to hydrogen gases, while exposed to varying temperatures. We will briefly discuss the transformer monitoring application, the device design and fabrication process, and the sensor performance from 21-months of testing. Transfer functions from oil temperature and dissolved gas concentration have been quantified, and those will be briefly discussed. These new sensors offer a novel alternative to electrochemical cell-based sensors for various applications. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Schottky diodes fabricated on cracked GaN epitaxial layer grown on (111) silicon

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005
Sung-Jong Park
Abstract The planar Schottky diodes were fabricated, characterized and modelled to study the electrical characteristics of cracked GaN epitaxial layer on (111) silicon substrate. We deposited Ti/Al/Ni/Au as the ohmic metal and Pt as the Schottky metal. The ohmic contact resistivity was 5.51 10,5 ,cm2 after annealing in N2 ambient at 700 C for 30 s. The fabricated Schottky diode exhibited the barrier height of 0.7 eV and the ideal factor was 2.4. We got the cutoff wavelength at 360 nm, peak responsivity of 0.097 A/W at 300 nm, and UV/visible rejection ratio was about 104. The SPICE simulation with the circuit model, which was composed with one Pt/GaN diode and three parasitic diodes, showed good agreement with the experiment. ( 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]