Hydrogenation of Gallium Nitride

1993 ◽  
Vol 325 ◽  
Author(s):  
M. S. Brandt ◽  
N. M. Johnson ◽  
R. J. Molnar ◽  
R. Singh ◽  
T. D. Moustakas
Keyword(s):  
Comparative Study ◽  
Conduction Band ◽  
Room Temperature ◽  
Hole Concentration ◽  
Conduction Band Edge ◽  
Order Of Magnitude ◽  
Si Doped ◽  
Donor State ◽  
P Type ◽  
Mg Doped

AbstractA comparative study of the effects of hydrogen in n-type (unintentionally and Si-doped) as well as p-type (Mg-doped) MBE-grown GaN is presented. Hydrogenation above 500°C reduces the hole concentration at room temperature in the p-type material by one order of magnitude. Three different microscopic effects of hydrogen are suggested: Passivation of deep defects and of Mg-acceptors due to formation of hydrogen-related complexes and the introduction of a hydrogenrelated donor state 100 meV below the conduction band edge.

Radiative Recombination and Carrier Lifetimes in Surface-Free GaAs Homostructures

1989 ◽  
Vol 163 ◽  
Author(s):  
L. M. Smith ◽  
D. J. Wolford ◽  
R. Venkatasubramanian ◽  
S.K. Ghandhi
Keyword(s):  
Room Temperature ◽  
Diffusion Constant ◽  
Near Band Edge ◽  
Time Resolved ◽  
Bulk Gaas ◽  
Carrier Lifetimes ◽  
Double Heterostructures ◽  
Order Of Magnitude ◽  
Si Doped ◽  
P Type

AbstractWe show that the radiative efficiencies and lifetimes of photoexcited carriers in epitaxial GaAs may be enhanced by 3 to 4 orders-of-magnitude by the preparation of n+, doped layers at surface and substrate interfaces. Samples were prepared by Organo-Metallic Vapor Phase Epitaxy (OMVPE), with n-region thicknesses of 3–10 µm, and narrow layers Si-doped to n+ concentrations of 5×1018 cm-3. Time-resolved luminescence in such structures, under both surface and bulk (near-band-edge) excitation conditions, reveal near-edge-excitonic or band-to-band-dominated recombination spectra, with carrier lifetimes ranging from 1.5 nsec at 1.5 K to nearly 1 µsec at room temperature. This is in contrast to the sub-nanosecond lifetimes typical in conventionally prepared bulk GaAs, but is comparable to the best reported for high-purity LPE-prepared GaAs/AlxGa1-xAs double heterostructures. The spatial distributions of photoexcited carriers in these structures are observed to expand by over an order of magnitude during their 1 µsec room temperature lifetime. The expansion is diffusive, with a measured diffusion constant of 14 cm2/sec at 300 K. This corresponds to a room temperature mobility of 525 cm2/Vsec, comparable to previously measured hole mobilities in bulk p-type GaAs of similar purity. These results are clear evidence that the narrow, heavily doped layers effectively “shield” minority carriers from the interfaces, thereby reducing interface recombination.

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.

GalnAsSb Materials for Thermophotovoltaics

1996 ◽  
Vol 450 ◽  
Author(s):  
C. A. Wang ◽  
G. W. Turner ◽  
M. J. Manfra ◽  
H. K. Choi ◽  
D. L. Spears
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Hole Concentration ◽  
Organometallic Vapor Phase Epitaxy ◽  
Room Temperature Photoluminescence ◽  
P Type ◽  
First Time ◽  
Lattice Matched ◽  
Comparable Quality ◽  
Peak Emission

ABSTRACTGai1−xInxASySb1-y (0.06 < x < 0.18, 0.05 < y < 0.14) epilayers were grown lattice-matched to GaSb substrates by low-pressure organometallic vapor phase epitaxy (OMVPE) using triethylgallium, trimethylindium, tertiarybutylarsine, and trimethylantimony. These epilayers have a mirror-like surface morphology, and exhibit room temperature photoluminescence (PL) with peak emission wavelengths (λP,300K) out to 2.4 μm. 4K PL spectra have a full width at half-maximum of 11 meV or less for λP,4K < 2.1 μm (λP,300K = 2.3 μm). Nominally undoped layers are p-type with typical 300K hole concentration of 9 × 1015 cm−3 and mobility ∼ 450 to 580 cm2/V-s for layers grown at 575°C. Doping studies are reported for the first time for GalnAsSb layers doped n type with diethyltellurium and p type with dimethylzinc. Test diodes of p-GalnAsSb/n-GaSb have an ideality factor that ranges from 1.1 to 1.3. A comparison of electrical, optical, and structural properties of epilayers grown by molecular beam epitaxy indicates OMVPE-grown layers are of comparable quality.

scholarly journals Self-Assembled Vanadium Oxide Nanoflakes for p-Type Ammonia Sensors at Room Temperature

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 317 ◽  
Author(s):  
Haihong Yin ◽  
Changqing Song ◽  
Zhiliang Wang ◽  
Haibao Shao ◽  
Yi Li ◽  
...  
Keyword(s):  
Vanadium Oxide ◽  
Room Temperature ◽  
Gas Sensing ◽  
Electron Microscopies ◽  
Ammonia Sensing ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Self Assembled ◽  
Ammonia Sensors ◽  
P Type

VO2(B), VO2(M), and V2O5 are the most famous compounds in the vanadium oxide family. Here, their gas-sensing properties were investigated and compared. VO2(B) nanoflakes were first self-assembled via a hydrothermal method, and then VO2(M) and V2O5 nanoflakes were obtained after a heat-phase transformation in nitrogen and air, respectively. Their microstructures were evaluated using X-ray diffraction and scanning and transmission electron microscopies, respectively. Gas sensing measurements indicated that VO2(M) nanoflakes were gas-insensitive, while both VO2(B) and V2O5 nanoflakes were highly selective to ammonia at room temperature. As ammonia sensors, both VO2(B) and V2O5 nanoflakes showed abnormal p-type sensing characteristics, although vanadium oxides are generally considered as n-type semiconductors. Moreover, V2O5 nanoflakes exhibited superior ammonia sensing performance compared to VO2(B) nanoflakes, with one order of magnitude higher sensitivity, a shorter response time of 14–22 s, and a shorter recovery time of 14–20 s. These characteristics showed the excellent potential of V2O5 nanostructures as ammonia sensors.

Optical and EPR Study of Defects in Cadmium Germanium Arsenide

2002 ◽  
Vol 744 ◽  
Author(s):  
Lihua Bai ◽  
N. Y. Garces ◽  
Nanying Yang ◽  
P. G. Schunemann ◽  
S. D. Setzler ◽  
...  
Keyword(s):  
Absorption Band ◽  
Optical Absorption ◽  
Room Temperature ◽  
Hole Concentration ◽  
Paramagnetic Defect ◽  
Paramagnetic Resonance ◽  
Anion Site ◽  
Shallow Acceptors ◽  
P Type ◽  
Cadmium Germanium Arsenide

ABSTRACTBulk crystals of CdGeAs2 have been characterized using photoluminescence (PL), optical absorption, Hall effect, and electron paramagnetic resonance (EPR) techniques. An absorption band near 5.5 microns at room temperature is observed in all of the p-type samples we have studied. A correlation between the magnitude of this optical absorption and the excess hole concentration at room temperature is established. Also, an EPR signal is found to correlate with the strength of this absorption band. PL data are consistent with an increased concentration of shallow acceptors being present in high-absorption samples. From the EPR data, we suggest that a model for the paramagnetic defect associated with the absorption at 5.5 microns may be an acceptor on an anion site.

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

Photoluminescence Characterization of p-type GaN:Mg

1997 ◽  
Vol 482 ◽  
Author(s):  
Dorina Corlatan ◽  
Joachim Krüger ◽  
Christian Kisielowski ◽  
Ralf Klockenbrink ◽  
Yihwan Kim ◽  
...  
Keyword(s):  
Layer Structure ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Near Band Edge ◽  
Acceptor Pair ◽  
Donor Acceptor ◽  
Si Doped ◽  
P Type ◽  
Mg Doped

AbstractWe report on results of low-temperature photoluminescence measurements performed on GaN films, grown by molecular beam epitaxy (MBE) on sapphire substrates. The GaN films are either Mg doped (p-type) or consist of a Mg-doped layer on top of a Si doped GaN layer (n-type). In the p-doped samples, the sharpness of the donor-acceptor-pair transition is striking, three phonon replicas are clearly resolved. A transition band occurs around 3.4 eV, which becomes dominant for samples with an np-layer structure. The position and the composition of the near band edge transitions are influenced by the growth of the buffer layers. Depending on the growth conditions a transition at 3.51 eV can be observed.

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.

Recombination and Electronic Transport in Low-Gap a-Si,Ge:H,F Alloys

1987 ◽  
Vol 95 ◽  
Author(s):  
S. Aljishi ◽  
D. S. Shen ◽  
V. Chu ◽  
Z E. Smith ◽  
J. P. Conde ◽  
...  
Keyword(s):  
Conduction Band ◽  
Electronic Transport ◽  
Room Temperature ◽  
Dark Conductivity ◽  
Electron Trapping ◽  
Conduction Band Edge ◽  
Band Tail ◽  
Intensity Dependence ◽  
Defect Densities ◽  
Deposition Conditions

AbstractWe have studied the temperature and intensity dependence (130K to 300K) of photo- and dark conductivity in a series of low-gap a-Si,Ge:H,F alloys (Eopt=1.25 to 1.33 eV) prepared under different deposition conditions. Electron time of flight experiments were conducted between 300K and 400K. Results reveal an increase in the slope of the exponential conduction band tail to ∼ 50 meV and a peak in electron trapping states at 0.3 to 0.4 eV below the conduction band edge, leading to a transition from extended to hopping conduction by electrons at slightly below room temperature. The alloys have midgap defect densities in the low 1017 cm−3eV−1 range.

The Dependence of the Magnetic Properties of GaMnN on Codoping by Mg and Si

2004 ◽  
Vol 834 ◽  
Author(s):  
Mason J. Reed ◽  
M. Oliver Luen ◽  
Meredith L. Reed ◽  
Salah M. Bedair ◽  
Fevzi Erdem Arkun ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Fermi Level ◽  
Energy Band ◽  
Room Temperature ◽  
Dopant Concentration ◽  
Room Temperature Ferromagnetism ◽  
Chemical Vapor ◽  
Material System ◽  
Si Doped ◽  
Mg Doped

ABSTRACTThe magnetic properties of GaMnN, grown by metalorganic chemical vapor deposition, depend on the addition of dopants; where undoped materials are ferromagnetic, and n -type (Si-doped) and p -type (Mg-doped) films are either ferromagnetic or paramagnetic depending on dopant concentration. The ferromagnetism of this material system seems correlated to Fermi level position, and is observed only when the Fermi level is within or close to the Mn energy band. This allows ferromagnetism-mediating carriers to be present in the Mn energy band. The current results exclude precipitates or clusters as the origin of room temperature ferromagnetism in GaMnN.

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