Ultraviolet Photodetection Properties of ZnO Microtubes

2006 ◽  
Vol 957 ◽  
Author(s):  
Jiping Cheng ◽  
Ming Fu ◽  
Yunjin Zhang ◽  
Ruyan Guo
Keyword(s):  
Low Cost ◽  
Optical Filters ◽  
Wide Bandgap ◽  
Low Power Consumption ◽  
Uv Detectors ◽  
Solar Blind ◽  
High Efficient ◽  
Potential Applications ◽  
Growth Method ◽  
Bandgap Semiconductors

ABSTRACTPhotodetectors based on wide-bandgap semiconductors have demonstrated several advantages over traditional ultraviolet (UV) detectors (photomultiplier tubes and Si-based UV detectors) such as low power consumption, high stability, and no need of other optical filters. ZnO stands a good chance of being a candidate material for solar-blind UV detection because of its direct bandgap of 3.37eV and high photoresponse. In this work, single crystal ZnO microtubes synthesized using a microwave-heating growth method and their UV photodetection properties were studied. The ZnO microtubes exhibited relatively fast UV photoresponse with a cut-off wavelength ∼370 nm, indicating their potential applications as high efficient and low cost UV detectors.

Growth of Low-Defect SiC and AlN Crystals in Refractory Metal Crucibles

2013 ◽  
Vol 740-742 ◽  
pp. 85-90 ◽  
Author(s):  
Heikki I. Helava ◽  
Evgeny N. Mokhov ◽  
Oleg A. Avdeev ◽  
Mark G. Ramm ◽  
Dmitri P. Litvin ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Refractory Metal ◽  
Lower Cost ◽  
Low Cost ◽  
Wide Bandgap ◽  
Tantalum Carbide ◽  
Metal Carbide ◽  
Metal Carbides ◽  
High Quality ◽  
Bandgap Semiconductors

Recently the wide bandgap semiconductors, silicon carbide (SiC) and aluminum nitride (AlN), have acquired increased importance due to the unique properties that make them applicable to a variety of rapidly-emerging, diverse technologies. In order to meet the challenges posed by these applications the materials need to be manufactured with the highest possible quality, both structural and chemical, at increasingly lower cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible. Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. The SiC group of Prof Yuri A Vodakov (for example, [1]) at Karmon Ltd in St Petersburg, Russia was the first to study and utilize the properties of refractory metal carbides, first for the growth of SiC and later for the growth of AlN. We discuss how the refractory metal carbides can answer many of the problems of growing SiC and AlN in a relatively simple and low cost manner.

scholarly journals Hot-Probe Characterization of Transparent Conductive Thin Films

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1186
Author(s):  
Alexander Axelevitch
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Low Cost ◽  
Transparent Conductive Oxide ◽  
Wide Bandgap ◽  
Cost Evaluation ◽  
Wide Bandgap Semiconductors ◽  
Hot Probe ◽  
Bandgap Semiconductors ◽  
Ito Films

Transparent conductive oxide (TCO) thin films represent a large class of wide-bandgap semiconductors applied in all fields of micro- and optoelectronics. The most widespread material applied for the creation of TCO coatings is indium-tin oxide (ITO). At the same time, there are plurality trends to change the high-cost ITO on other materials, for example, on the ZnO doped by different elements such as Al, Mn, and Sb. These films require mobile and low-cost evaluation methods. The dynamic hot-probe measurement system is one of such techniques that can supplement and sometimes replace existing heavy systems such as the Hall effect measurements or the Haynes–Shockley experiments. The theoretical basis and the method of analysis of the recorded dynamic hot-probe characteristics measured at different temperatures were presented in this work. This method makes it possible to extract the main parameters of thin films. Commercial thin ITO films and new transparent conducting ZnO:Al layers prepared by magnetron co-sputtering were studied by the proposed method. The measured parameters of commercial ITO films are in agreement with the presented and reference data. In addition, the parameters of ZnO:Al thin films such as the majority charge carriers type, concentration, and mobility were extracted from dynamic hot-probe characteristics. This method may be applied also to other wide-bandgap semiconductors.

A Study on Fastening the Switching Speed for Wide Bandgap Semiconductor Based Super Cascode

2019 ◽  
Vol 963 ◽  
pp. 823-826
Author(s):  
Xiang Guo Wang ◽  
Masayuki Yamamoto
Keyword(s):  
Low Voltage ◽  
Low Cost ◽  
Wide Bandgap ◽  
Common Source ◽  
Switching Speed ◽  
Wide Bandgap Semiconductor ◽  
Switching Losses ◽  
Bipolar Devices ◽  
Bandgap Semiconductors ◽  
Silicon Based

The Super Cascode is a series connected structure with a normally-off low voltage Si-MOSFET and multiple normally-on wide bandgap semiconductors. It has low switching losses compared with silicon based bipolar devices, and low on-resistance and low cost compared with other single high voltage normally-off wide bandgap semiconductor devices. In practice, however, there are inevitable parasitic inductances, which result in the increase of switching losses. The method is proposed to eliminate the common-source inductances (CSIs), such as using stack-die configuration with each device and adding an additional inductance in the gate loop of Si-MOSFET. It is numerically shown that the rise and fall times of the proposed method were 33.5% and 7.2% faster than the conventional one, respectively.

Recent Advances in Wide Bandgap Semiconductor Biological and Gas Sensors

2009 ◽  
Vol 1202 ◽  
Author(s):  
S.J. Pearton ◽  
F. Ren ◽  
Yu-Lin Wang ◽  
B. H. Chu ◽  
K. H. Chen ◽  
...  
Keyword(s):  
Homeland Security ◽  
Wide Bandgap ◽  
Detection Sensitivity ◽  
Semiconductor Surface ◽  
Wireless Data ◽  
Wireless Data Transmission ◽  
Solar Blind ◽  
Wide Energy ◽  
Bandgap Semiconductors ◽  
Uv Photons

AbstractThere has been significant recent interest in the use of surface-functionalized thin film and nanowire wide bandgap semiconductors, principally GaN, InN, ZnO and SiC, for sensing of gases, heavy metals, UV photons and biological molecules. For the detection of gases such as hydrogen, the semiconductors are typically coated with a catalyst metal such as Pd or Pt to increase the detection sensitivity at room temperature. Functionalizing the surface with oxides, polymers and nitrides is also useful in enhancing the detection sensitivity for gases and ionic solutions. The wide energy bandgap of these materials make them ideal for solar-blind UV detection, which can be of use for detecting fluorescence from biotoxins. The use of enzymes or adsorbed antibody layers on the semiconductor surface leads to highly specific detection of a broad range of antigens of interest in the medical and homeland security fields. We give examples of recent work showing sensitive detection of glucose, lactic acid, prostate cancer and breast cancer markers and the integration of the sensors with wireless data transmission systems to achieve robust, portable sensors.

GaN and Related Materials for Device Applications

MRS Bulletin ◽  
1997 ◽  
Vol 22 (2) ◽  
pp. 17-21 ◽  
Author(s):  
Stephen J. Pearton ◽  
Chihping Kuo
Keyword(s):  
Data Storage ◽  
Communication Systems ◽  
Light Emitting Diode ◽  
Shallow Donor ◽  
Photonic Devices ◽  
Uv Detectors ◽  
Solar Blind ◽  
Bandgap Semiconductors ◽  
1960S And 1970S ◽  
The 1960S

The addition of GaN, A1N, InN, and related alloys to the family of device-quality semiconductors has opened up new opportunities in short-wavelength (visible and ultraviolet [uv]) photonic devices for display and data-storage applications, solar-blind uv detectors, and high-temperature/high-power electronics. Silicon will of course continue to dominate in microelectronics applications, and InP and GaAs and their related alloys will be the mainstays of long-wavelength lightwave communication systems and red, orange, and yellow light-emitting-diode (LED) technology, respectively. There are however many existing and emerging uses for wide-bandgap semiconductors with good electrical and optical characteristics. The purpose of this issue of MRS Bulletin is to furnish a background and summary on the exciting new developments involving GaN and related materials.Strong efforts on the synthesis and device aspects of GaN took place in the 1960s and 1970s because of the potential for realization of blue lasers and LEDs that would extend the existing wavelength range of photonic devices. Progress was hampered because of several severe materials problems. First there was no bulk crystal growth technology for producing substrates, and epitaxial material was grown on highly lattice-mismatched substrates such as sapphire. This heteroepitaxial material was invariably highly conducting because of residual shallow donor defects or impurities. These high n-type backgrounds, combined with the relatively deep ionization levels of all of the common p-type dopant impurities, prevented the achievement of p-type doping and therefore of bipolar or injection devices.

Sublimation Growth of 4 and 6 Inch 4H-SiC Low Defect Bulk Crystals in Ta (TaC) Crucibles

2016 ◽  
Vol 858 ◽  
pp. 101-104
Author(s):  
Yu.N. Makarov ◽  
D. Litvin ◽  
A. Vasiliev ◽  
S. Nagalyuk
Keyword(s):  
Refractory Metal ◽  
Low Cost ◽  
Large Diameter ◽  
Wide Bandgap ◽  
Tantalum Carbide ◽  
Metal Carbides ◽  
Bulk Crystals ◽  
Bandgap Semiconductors ◽  
Sublimation Growth ◽  
First Time

Recently, the wide bandgap semiconductors, especially silicon carbide (SiC), have become more important due to the unique electrical and thermophysical properties that make them applicable to a variety of electronic devices (Schottky and PiN diodes, JFETs, MOSFETs, etc.). For these applications, the crystals need to be manufactured with highest possible quality, both structural and chemical, at reduced cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible.Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. Yu. Vodakov [1] demonstrated for the first time advantages of use of refractory metal carbides for PVT growth of SiC and later AlN bulk crystals. In the present paper we discuss the effect of refractory metal on PVT growth of large diameter 4H SiC bulk crystals.

Power Electronic Devices and Systems Based on Bulk GaN Substrates

2018 ◽  
Vol 924 ◽  
pp. 799-804 ◽  
Author(s):  
Eric P. Carlson ◽  
Daniel W. Cunningham ◽  
Yan Zhi Xu ◽  
Isik C. Kizilyalli
Keyword(s):  
High Voltage ◽  
Wide Bandgap ◽  
Performance Limits ◽  
Wide Bandgap Semiconductors ◽  
Power Semiconductor ◽  
Power Transistors ◽  
Wide Range ◽  
Potential Applications ◽  
Bulk Gan ◽  
Bandgap Semiconductors

Wide-bandgap power semiconductor devices offer enormous energy efficiency gains in a wide range of potential applications. As silicon-based semiconductors are fast approaching their performance limits for high power requirements, wide-bandgap semiconductors such as gallium nitride (GaN) and silicon carbide (SiC) with their superior electrical properties are likely candidates to replace silicon in the near future. Along with higher blocking voltages wide-bandgap semiconductors offer breakthrough relative circuit performance enabling low losses, high switching frequencies, and high temperature operation. ARPA-E’s SWITCHES program, started in 2014, set out to catalyze the development of vertical GaN devices using innovations in materials and device architectures to achieve three key aggressive targets: 1200V breakdown voltage (BV), 100A single-die diode and transistor current, and a packaged device cost of no more than ȼ10/A. The program is drawing to a close by the end of 2017 and while no individual project has yet to achieve all the targets of the program, they have made tremendous advances and technical breakthroughs in vertical device architecture and materials development. GaN crystals have been grown by the ammonothermal technique and 2-inch GaN wafers have been fabricated from them. Near theoretical, high-voltage (1700-4000V) and high current (up to 400A pulsed) vertical GaN diodes have been demonstrated along with innovative vertical GaN transistor structures capable of high voltage (800-1500V) and low RON (0.36-2.6 mΩ-cm2). The challenge of selective area doping, needed in order to move to higher voltage transistor devices has been identified. Furthermore, a roadmap has been developed that will allow high voltage/current vertical GaN devices to reach ȼ5/A to ȼ7/A, realizing functional cost parity with high voltage silicon power transistors.

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