Preparation and Characterization of 3C-SiC Heteroepitaxial Layers on Si(111)

1992 ◽  
Vol 242 ◽  
Author(s):  
Mitsugu Yamanaka ◽  
Keiko Ikoma
Keyword(s):  
Hall Mobility ◽  
Carrier Density ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Similar Temperature Dependence ◽  
Temperature Dependences ◽  
Similar Temperature ◽  
First Time ◽  
Heteroepitaxial Layers

ABSTRACT3C-SiC layers were grown on Si(111) substrates by chemical vapor deposition (CVD) using SiH4-CH3CI-H2 gas mixture. 3C-SiC(111) heteroepitaxial layers were obtained with smooth surfaces and reduced warpage. All the epilayers were n- type, and the carrier density and Hall mobility were 2.1×1016∼2.8×1017 cm-3 and 120∼180 cm2/Vs at room temperature, respectively. Temperature dependences of the electrical properties of the self-supported 3C-SiC(111) epilayers were measured between 15 and 300 K for the first time. 3C-SiC(111) epilayers showed a similar temperature dependence of carrier density to 3C-SiC(001) heteroepitaxial layer. Hall mobility was maximum (∼360 cm2/Vs) around 100 K.

scholarly journals Synthesis and electrical characterization of Ca2Nd4Ti6O20 ceramics

2016 ◽  
Vol 34 (1) ◽  
pp. 164-168
Author(s):  
Raz Muhammad ◽  
Muhammad Uzair ◽  
M. Javid Iqbal ◽  
M. Jawad Khan ◽  
Yaseen Iqbal ◽  
...  
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Room Temperature ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Sintered Sample ◽  
First Time ◽  
Alkoxide Precursors ◽  
Room Temperature Dielectric Constant

AbstractCa2Nd4Ti6O20, a layered perov skite structured material was synthesized via a chemical (citrate sol-gel) route for the first time using nitrates and alkoxide precursors. Phase analysis of a sample sintered at 1625 °C revealed the formation of an orthorhombic (Pbn21) symmetry. The microstructure of the sample after sintering comprised rod-shaped grains of a size of 1.5 to 6.5µm. The room temperature dielectric constant of the sintered sample was 38 at 100 kHz. The remnant polarization (Pr) and the coercive field (Ec) were about 400 μC/cm2 and 8.4 kV/cm, respectively. Impedance spectroscopy revealed that the capacitance (13.7 pF) and activation energy (1.39 eV) of the grain boundary was greater than the capacitance (5.7 pF) and activation energy (1.13 eV) of the grain.

Microstructural and Optical Characterization of GaN Films Grown by PECVD on (0001) Sapphire Substrates

1989 ◽  
Vol 162 ◽  
Author(s):  
T. P. Humphreys ◽  
C. A. Sukow ◽  
R. J. Nemanich ◽  
J. B. Posthill ◽  
R. A. Rudder ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Optical Characterization ◽  
Epitaxial Films ◽  
Optical And Electrical Properties ◽  
Spectroscopy Data ◽  
Sapphire Substrates ◽  
Cubic Gan ◽  
First Time

ABSTRACTEpitaxial GaN films have been grown by plasma-enhanced chemical vapor deposition (PECVD). The growth procedure utilizes a He gas discharge combined with the down-stream introduction of trimethylgallium (TMGa) and nitrogen. Both cubic [1111 and wurtzitic [0001] GaN epitaxial films have been achieved on (0001) sapphire substrates. Differences in substrate growth temperatures are believed to account for the different observed phases. A comparative study pertaining to the microstructural, optical and electrical properties of the α-GaN and β-GaN heteroepitaxial films is presented. Also reported for the first time is the Raman spectroscopy data for cubic GaN.

Characterization of a Large Area Silicon Carbide PiN Diode at Temperatures up to 900°C

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000384-000387 ◽  
Author(s):  
Jim Richmond ◽  
Lin Cheng ◽  
Anant Agarwal ◽  
John Palmour
Keyword(s):  
Silicon Carbide ◽  
Room Temperature ◽  
Extreme Temperature ◽  
Temperature Gradients ◽  
Pin Diode ◽  
Large Area ◽  
Chip Area ◽  
Electrical Connections ◽  
First Time

For the first time, a large area Silicon Carbide (SiC) PiN diode was measured to determine the forward and reverse characteristics at temperatures up to 900°C. The diode characterized had a chip area of 64 mm2 and used a conventional SiC PiN structure with a 75 um N type blocking layer thickness. A normal rating for this device at room temperature would be 50 amps at 100 A/cm2 and 6 kV. Since a package capable of operating at 900°C was not available, methods were developed to heat and verify the temperature of the diode die, provide electrical connections to the die and provide adequate insulation to minimize temperature gradients across the die. Even at this extreme temperature the diode maintained typical diode characteristics and maintained surprisingly good performance.

Quadrol-Pd(II) complexes: phosphine-free precatalysts for the room-temperature Suzuki-Miyaura synthesis of nucleoside analogues in aqueous media

2022 ◽  
Author(s):  
Jose Luis Serrano ◽  
Sujeet Gaware ◽  
Jose Antonio Pérez de Haro ◽  
Jose Pérez ◽  
Pedro Lozano ◽  
...  
Keyword(s):  
Room Temperature ◽  
Aqueous Media ◽  
Water Soluble ◽  
Nucleoside Analogues ◽  
Synthesis And Characterization ◽  
First Time

Commercially available Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (THPEN), has been used for the first time as N^N- donor neutral hydrophilic ligand in the synthesis and characterization of new water soluble palladium (II) complexes...

Optoelectronic Characterization of Infrared Photodetector Fabricated on Ge-on-Si Substrate

2015 ◽  
Vol 15 (10) ◽  
pp. 7832-7835 ◽  
Author(s):  
Zagarzusem Khurelbaatar ◽  
Yeon-Ho Kil ◽  
Taek Sung Kim ◽  
Kyu-Hwan Shim
Keyword(s):  
Vapor Deposition ◽  
Room Temperature ◽  
Doping Concentration ◽  
Reverse Bias ◽  
Chemical Vapor ◽  
Antireflection Coating ◽  
Infrared Photodetector ◽  
Si Substrate ◽  
Thermal Chemical Vapor Deposition

We report on the optoelectronic characterization of Ge p–i–n infrared photodetector fabricated on Ge-on-Si substrate using rapid thermal chemical vapor deposition (RTCVD). The phosphorous doping concentration and the root mean square (RMS) surface roughness of epitaxial layer was estimated to be 2 × 1018 cm–3 and 1.2 nm, respectively. The photodetector were characterized with respect to their dark, photocurrent and responsivities in the wavelength range of 1530–1630 nm. At 1550 nm wavelength, responsivity of 0.32 A/W was measured for a reverse bias of 1 V, corresponding to 25% external quantum efficiency, without an optimal antireflection coating. Responsivity drastically reduced from 1560 nm wavelength which could be attributed to decreased absorption of Ge at room temperature.

Gallium Nitride Based Semiconductors for Short Wavelength Optoelectronics

1997 ◽  
Vol 08 (02) ◽  
pp. 265-282
Author(s):  
S. P. Denbaars
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Chemical Vapor ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Film Properties ◽  
Full Color ◽  
Color Spectrum ◽  
First Time ◽  
Room Temperature Operation

In this article we review the key technologies for GaN based materials and devices. Developments in the methods for thin film deposition by metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) and resulting film properties are highlighted. Breakthroughs in materials growth has enabled extremely high efficiency blue and green GaN LEDs to be achieved for the first time. GaN LEDs complete the primary color spectrum and have enabled bright and reliable full-color solid state displays to be realized. Recently, room temperature operation of pulsed current injection blue-violet lasers emitting at 417 nm has further increased possible applications for GaN based optoelectronic devices.

THE GROWTH AND CHARACTERIZATION OF ROOM TEMPERATURE FERROMAGNETIC WIDEBAND-GAP MATERIALS FOR SPINTRONIC APPLICATIONS

2006 ◽  
Vol 16 (02) ◽  
pp. 515-543
Author(s):  
MATTHEW H. KANE ◽  
MARTIN STRASSBURG ◽  
WILLIAM E. FENWICK ◽  
ALI ASGHAR ◽  
IAN T. FERGUSON
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Room Temperature Ferromagnetism ◽  
Dilute Magnetic Semiconductors ◽  
Chemical Vapor ◽  
Wide Bandgap ◽  
Organic Chemical ◽  
Ferromagnetic Behavior ◽  
Spintronic Devices

Wide-bandgap dilute magnetic semiconductors (DMS), such as transition-metal doped ZnO and GaN , have gained attention for use in spintronic devices because of predictions and experimental reports of room temperature ferromagnetism which may enable their use in spintronic devices. However, there has been some debate over the source of ferromagnetism in these materials. This paper focuses on the high quality growth of wide bandgap DMS, and the characterization of Zn 1-x Mn x O produced by melt-growth techniques and Ga 1-x Mn x N grown by metal organic chemical vapor deposition (MOCVD). High resolution X-ray diffraction results revealed no second phases in either the ZnO crystals or the GaN films. Undoped as-grown, bulk crystals of Zn 1-x Mn x O and Zn 1-x Co x O crystals are shown to be paramagnetic at all temperatures. In contrast, the Ga 1-x Mn x N films showed ferromagnetic behavior at room temperature under optimum growth conditions. Experimental identification of the Mn ion charge state and the presence of bands in the bandgap of GaN are investigated by optical spectroscopy and electron spin paramagnetic resonance (EPR). It is shown that the broadening of states in the Mn 3d shell scaled with Mn concentration, and that optical transitions due to this band correlated with the strong ferromagnetism in these samples. However, this band disappeared with an increase in free electron concentration provided by either annealing or doping. Raman studies of Ga 1-x Mn x N revealed two predominant Mn -related modes featured with increasing concentration, a broad disorder related structure at 300cm-1 and a sharper peak at 669cm-1 This works show that the development of practical ferromagnetic wide bandgap DMS materials for spintronic applications will require both the lattice site introduction of Mn as well as careful control of the background defect concentration to optimize these materials.

Synthesis and characterization of single-crystal indium nitride nanowires

2004 ◽  
Vol 19 (2) ◽  
pp. 423-426 ◽  
Author(s):  
Tao Tang ◽  
Song Han ◽  
Wu Jin ◽  
Xiaolei Liu ◽  
Chao Li ◽  
...  
Keyword(s):  
Electronic Transport ◽  
Room Temperature ◽  
Thermal Emission ◽  
Indium Nitride ◽  
Chemical Vapor ◽  
Gold Clusters ◽  
Vapor Generation ◽  
Vapor Deposition Technique ◽  
Single Nanowires

InN nanowires were synthesized and characterized using a variety of techniques. A two-zone chemical vapor deposition technique was used to operate the vapor generation and the nanowire growth at differential temperatures, leading to high-quality single-crystalline nanowires and growth rates as high as 4–10 μm/h. Precise diameter control was achieved by using monodispersed gold clusters as the catalyst. Photoluminescence and Raman studies have been carried out for the InN nanowires at room temperature. Devices consisting of single nanowires have been fabricated to explore their electronic transport properties. The temperature dependence of the conductance revealed thermal emission as the dominating transport mechanism.

scholarly journals A GaN/4H-SiC heterojunction bipolar transistor with operation up to 300°C

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
John T Torvik ◽  
M. Leksono ◽  
J. I. Pankove ◽  
B. Van Zeghbroeck
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Bipolar Transistors ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain ◽  
Device Structure ◽  
Fabrication And Characterization ◽  
Dc Current

We report on the fabrication and characterization of GaN/4H-SiC n-p-n heterojunction bipolar transistors (HBTs). The device structure consists of an n-SiC collector, p-SiC base, and selectively grown n-GaN emitter. The HBTs were grown using metalorganic chemical vapor deposition on SiC substrates. Selective GaN growth through a SiO2 mask was used to avoid damage that would be caused by reactive ion etching. In this report, we demonstrate common base transistor operation with a modest dc current gain of 15 at room temperature and 3 at 300°C.

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