Persistent Photoconductivity in p-Type 4H-SiC Bulk Crystals

2013 ◽  
Vol 740-742 ◽  
pp. 413-416 ◽  
Author(s):  
Takafumi Okuda ◽  
Hiroki Miyake ◽  
Tsunenobu Kimoto ◽  
Jun Suda
Keyword(s):  
Decay Time ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Persistent Photoconductivity ◽  
Bulk Crystals ◽  
Decay Times ◽  
Photoconductivity Decay ◽  
Increasing Temperature ◽  
P Type ◽  
Homoepitaxial Layers

We investigated the photoconductivity decay characteristics of p-type 4H-SiC bulk crystals grown by a modified Lely method by differential microwave photoconductance decay (μ-PCD) measurements using a 349-nm laser as an excitation source. We observed persistent photoconductivity (PPC) in the p-type SiC bulk crystals. The decay time at room temperature was 2600 μs. The decay time decreased with increasing temperature, resulting in 120 μs at 250oC, and the activation energy of the decay times was determined to be 140±10 meV. Long decay characteristics were also observed by below-band-gap excitation at 523 or 1047 nm. On the other hand, no PPC was observed in p-type homoepitaxial layers grown by hot-wall chemical vapor deposition.

The Properties of GaInAsSb/GaSb Heterostructure Grown by Mocvd and P-GaInAsSb/N-GaSb Photodiodes

1995 ◽  
Vol 415 ◽  
Author(s):  
Baolin Zhang ◽  
Yixin Jin ◽  
Tianming Zhou ◽  
Hong Jiang ◽  
Yongqiang Ning ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Room Temperature ◽  
Metalorganic Chemical Vapor Deposition ◽  
Hole Concentration ◽  
Chemical Vapor ◽  
Infrared Transmission ◽  
Long Wavelength ◽  
Measurement Results ◽  
P Type ◽  
Metalorganic Chemical

ABSTRACTGaInAsSb/GaSb heterostructures have been grown by metalorganic chemical vapor deposition (MOCVD). The optical properties were characterized using low temperature(71K) photoluminescence(PL) and infrared transmission spectroscopy. The FWHM of the typical PL spectrum peaked at 2.3μm is 30meV. Hall measurement results for undoped GaInAsSb layers are presented showing a p-type background and low hole concentration of 6.5 × 1015cm−3. The room temperature performances of the p-GaInAsSb/n-GaSb photodiodes are reported. Its responsivity spectrum is peaked at 2.2 5μm and cuts off at 1.7μm in the short wavelength and at 2.4μm in the long wavelength, respectively. The room temperature detectivity D* is of 1 × 109cm.Hz1/2.W−2

Manipulation of Room Temperature Ferromagnetic behavior of GaMnN Epilayers

2009 ◽  
Vol 1198 ◽  
Author(s):  
Neeraj Nepal ◽  
M. Oliver Luen ◽  
Pavel Frajtag ◽  
John Zavada ◽  
Salah M. Bedair ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hole Concentration ◽  
Chemical Vapor ◽  
Multilayer Structures ◽  
Organic Chemical ◽  
Ferromagnetic Behavior ◽  
Chemical Vapor Deposition Growth ◽  
Metal Organic ◽  
P Type ◽  
Organic Chemical Vapor Deposition

AbstractWe report on metal organic chemical vapor deposition growth of GaMnN/p-GaN/n-GaN multilayer structures and manipulation of room temperature (RT) ferromagnetism (FM) in a GaMnN layer. The GaMnN layer was grown on top of a n-GaN substrate and found to be almost always paramagnetic. However, when grown on a p-type GaN layer, a strong saturation magnetization (Ms) was observed. Ms was almost doubled after annealing demonstrating that the FM observed in GaMnN film is carrier-mediated. To control the hole concentration of the p-GaN layer by depletion, GaMnN/p-GaN/n-GaN multilayer structures of different p-GaN thickness (Xp) were grown on sapphire substrates. We have demonstrated that the FM depends on the Xp and the applied bias to the GaN p-n junction. The FM of these multilayer is independent on the top GaMnN layer thickness (tGaMnN) for tGaMnN >200 nm and decreases for tGaMnN < 200 nm. Thus the room temperature FM of GaMnN i-p-n structure can also be controlled by changing Xp and tGaMnN in the GaMnN i-p-n structures.

Long Photoconductivity Decay Characteristics in p-Type 4H-SiC Bulk Crystals

2013 ◽  
Vol 52 (1R) ◽  
pp. 010202 ◽  
Author(s):  
Takafumi Okuda ◽  
Hiroki Miyake ◽  
Tsunenobu Kimoto ◽  
Jun Suda
Keyword(s):  
Bulk Crystals ◽  
Photoconductivity Decay ◽  
P Type

Excess Carrier Lifetimes in a Bulk p-Type SiC Wafer Measured by the Microwave Photoconductivity Decay Method

2007 ◽  
Vol 556-557 ◽  
pp. 359-362 ◽  
Author(s):  
Masahiko Kawai ◽  
Tatsuhiro Mori ◽  
Masashi Kato ◽  
Masaya Ichimura ◽  
Shingo Sumie ◽  
...  
Keyword(s):  
Time Constant ◽  
Minority Carrier ◽  
Slow Component ◽  
Structural Defects ◽  
Excess Carrier ◽  
Carrier Lifetimes ◽  
Photoconductivity Decay ◽  
Increasing Temperature ◽  
P Type ◽  
Sic Wafer

We carried out mapping of the excess carrier lifetime for a bulk p-type 4H-SiC wafer by the microwave photoconductivity decay (μ-PCD) method, and we compared the lifetime map with structural defect distribution. Several small regions with short lifetimes compared with surrounding parts are found, and they correspond to regions with high-density structural defects. Excess carrier decay curves for this wafer show a slow component, which originates from minority carrier traps. From temperature dependence of the excess carrier decay curve, we found decrease of the time constant of the slow component with increasing temperature. We compared the activation energy of the time constant with that obtained from the numerical simulation, and concluded that the energy level for the minority carrier trap would be 125 meV from the conduction band.

Abklingzeitmessungen an Pseudoisocyanindiäthylchlorid mit einem Phasenfluorometer mit 200 MHz-Lichtmodulation

1969 ◽  
Vol 24 (5) ◽  
pp. 790-796 ◽  
Author(s):  
E. Michelbacher
Keyword(s):  
Temperature Dependence ◽  
Decay Time ◽  
Room Temperature ◽  
Modulation Frequency ◽  
Decay Times ◽  
Fluorescent Polymer

Abstract The decay time of pseudo-isocyanine (2,2 nsec at room temperature) has been measured by a phase fluorometer of 200 Me modulation frequency and its temperature dependence with respect to self absorption has been investigated. This allows to calculate the molecular decay time (1,7 nsec) and the number of molecules, which form the fluorescent polymer of the dye. Moreover the decay times of some p-oligophenylenes and the quenching effekt of nitrobencene on POPOP (1,82 nsec) have been measured.

Persistent Photoconductivity in p-Type GaN Epilayers and n-Type AlGaN/GaN Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
J. Z. Li ◽  
J. Y. Lin ◽  
H. X. Jiang ◽  
M. A. Khan ◽  
Q. Chen ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Persistent Photoconductivity ◽  
Dimensional Electron ◽  
Metal Organic ◽  
Dimensional Electron Gas ◽  
Gan Heterostructure ◽  
P Type ◽  
Organic Chemical Vapor Deposition

ABSTRACTPersistent photoconductivity (PPC) effect has been observed in p-type GaN epilayers grown both by metal-organic chemical vapor deposition (MOCVD) and reactive molecular beam epitaxy (MBE) as well as in a two-dimensional electron gas (2DEG) system formed by an AlGaN/GaN heterostructure grown by MOCVD. Its properties have been investigated at different conditions.

The effect of uniaxial stress on the persistent photoconductivity in Te-doped AlxGa1−xAs

1987 ◽  
Vol 65 (5) ◽  
pp. 505-509
Author(s):  
Eric Johnstone ◽  
Masamichi Sakamoto ◽  
Stefan Zukotynski ◽  
Ralph A. Logan
Keyword(s):  
Decay Time ◽  
Uniaxial Stress ◽  
Donor Level ◽  
Deformation Potential ◽  
Persistent Photoconductivity ◽  
Photoconductivity Decay

Persistent photoconductivity in Te-doped AlxGa1−xAs is measured. It is found that the photoconductivity rise is a phonon-assisted process. The photoconductivity decay time increases with the application of stress. From the dependence of conductivity on stress, the donor-level deformation potential is determined to be approximately 2 meV∙kbar−1 (1 bar = 100 kPa). Some evidence is presented that suggests that more than one DX-type level is required to explain the features of the persistent photoconductivity.

Epitaxial Growth and Properties of Mg-Doped Gan Film Produced by Atmospheric Mocvd System With Three Layered Lammar Flow Gas Injection

1997 ◽  
Vol 482 ◽  
Author(s):  
N. Akutsu ◽  
H. Tokunaga ◽  
I. Waki ◽  
A. Yamaguchi ◽  
K. Matsumoto
Keyword(s):  
Thermal Annealing ◽  
Room Temperature ◽  
Hole Concentration ◽  
Gas Injection ◽  
Chemical Vapor ◽  
Free Hole ◽  
Mg Doping ◽  
Doping Effects ◽  
P Type ◽  
Mg Doped

AbstractMg-doped GaN films with a variety of Mg concentrations were grown on sapphire (0001) by horizontal atmospheric metalorganic chemical vapor deposition (MOCVD) system with three layered laminar flow gas injection in an attempt to study the Mg doping effects on film quality. The increase of Mg concentration induced an increase of x-ray rocking curve full width at half maximum (FWHM) and degradation of surface morphology. Secondary ion mass spectroscopy (SIMS) analysis shows increase of Si and O, associated with Mg-doping concentration. Si and O concentrations of Mg-doped film are up to 5×1016cm−3 and 5×1017cm−3 at Mg concentration of 4.5×1019cm−3, respectively. Strong 380nm emission and weak 430nm emission were observed by photoluminescence (PL) measurement at room temperature for as-grown Mg-doped GaN films which shows p-type conductivity after thermal annealing. While, in highliy Mg-doped GaN films which do not show the p-type conduction after thermal annealing, 430nm and/or 450nm emission were dominating. The highest room temperature free hole concentration achieved was p=2.5× 1018cm−3 with mobility μp=l.9cm2/V s.

scholarly journals On the Structural, Morphological, and Electrical Properties of Carbon Nanowalls Obtained by Plasma-Enhanced Chemical Vapor Deposition

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Bogdan Bita ◽  
Sorin Vizireanu ◽  
Daniel Stoica ◽  
Valentin Ion ◽  
Sasa Yehia ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Plasma Treatment ◽  
Room Temperature ◽  
Chemical Vapour ◽  
Chemical Vapor ◽  
Current Voltage ◽  
Structural And Electrical Properties ◽  
Carbon Nanowalls ◽  
P Type ◽  
Top View

In this study, we investigated the morphological, structural, and electrical properties of carbon nanowall (CNW) structures obtained by plasma-enhanced chemical vapour deposition (PECVD) and underlined the induced effects of argon/nitrogen (Ar/N2) postsynthesis plasma treatment on the electrical behaviour. The top view and cross-section scanning electron microscopy micrographs revealed that the fabricated samples are about 18 μm height, and the edges are less than 10 nm. The Raman analysis showed the presence of the specific peaks of graphene-based materials, i.e., D-band, G-band, D′-band, 2D-band, and D+G-band. The average values of the electrical resistance of fabricated samples were evaluated by current-voltage characteristics acquired at room temperature, in the ranges of 0 V–0.2 V, and an increase was noticed with about 50% after the Ar/N2 postsynthesis plasma treatment compared to pristine samples. Moreover, the Hall measurements proved that the obtained CNW structures had p-type conductivity (Hall coefficient was 0.206 m3/C), and the concentration of charge carriers was 7.8×1019 cm-3, at room temperature.

Effect of Ion Doping Temperature on Electrical Properties of APCVD A-Si

1994 ◽  
Vol 336 ◽  
Author(s):  
Kyung Ha Lee ◽  
Byeong Yeon Moon ◽  
Yoo Chan Chung ◽  
Seung Min Lee ◽  
Sung Chul Kim ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Hydrogen Incorporation ◽  
Ion Doping ◽  
Pressure Chemical ◽  
Si Films ◽  
P Type

ABSTRACTWe have studied the effect of ion doping on the electrical properties for atmospheric pressure chemical vapor deposition (APCVD) Amorphous silicon (a-Si) films. The room temperature conductivities after ion doping at optimum doping temperatures for n- and p-type a-Si films were found to be > 10−2 and > 10−4 S/cm, respectively. The unintentional hydrogen incorporation into a-Si during ion doping enhances the quality of ion doped APCVD a-Si as compared to that of plasma enhanced CVD (PECVD) a-S.i.H. We obtained the field effect mobility of > 1 cm2/Vs for APCVD a-Si TFT using ion doped n+-layer.

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