Molecular-beam study of the activation energy requirements for the dioxetane reaction

1978 ◽  
Vol 100 (11) ◽  
pp. 3274-3278 ◽  
Author(s):  
K. T. Alben ◽  
A. Auerbach ◽  
W. M. Ollison ◽  
J. Weiner ◽  
R. J. Cross
Keyword(s):  
Activation Energy ◽  
Molecular Beam ◽  
Energy Requirements

ChemInform Abstract: MOLECULAR-BEAM STUDY OF THE ACTIVATION ENERGY REQUIREMENTS FOR THE DIOXETANE REACTION

1978 ◽  
Vol 9 (35) ◽  
Author(s):  
K. T. ALBEN ◽  
A. AUERBACH ◽  
W. M. OLLISON ◽  
J. WEINER ◽  
R. J. JUN. CROSS
Keyword(s):  
Activation Energy ◽  
Molecular Beam ◽  
Energy Requirements

Elevated Temperature Characteristics of Carbon-Doped GaInP/GaAs Heterojunction Bipolar Transistor Grown by Solid Source Molecular Beam Epitaxy

2003 ◽  
Vol 799 ◽  
Author(s):  
Zhang Rong ◽  
Yoon Soon Fatt ◽  
Tan Kianhua ◽  
Sun Zhongzhe ◽  
Huang Qingfeng
Keyword(s):  
Activation Energy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Base Material ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Collector Current ◽  
Carbon Doped ◽  
Base Current ◽  
Recombination Current

ABSTRACTThis paper reports the characteristics of GaInP/GaAs heterojunction bipolar transistor (HBT) with carbon-doped GaAs base layer grown by solid source molecular beam epitaxy (SSMBE) using carbon tetrabromide (CBr4) as p-type dopant precursor. Hydrofluoric acid (HF) was used to passivate the GaInP/GaAs HBTs. At base bias voltages below 0.8V in the Gummel plot, the base current of large-area devices after HF treatment was greatly reduced. This indicates that the extrinsic base surface recombination current was greatly reduced. After HF treatment, detailed DC characterization of the device performance from 300K to 380K was carried out and the carrier transport properties were investigated. The base current and collector current ideality factors at 300K were 1.12 and 1.01, respectively. This indicates that the space- charge region recombination current in the base is insignificant. From the temperature- dependent Gummel plot, the activation energies of collector current and base current were obtained. For the collector current, the activation energy is 1.4eV, which is close to the bandgap of the GaAs base. This indicates that the collector current is determined by the drift-diffusion process, in which an energy barrier of the same magnitude as the base bandgap is to be overcome by electrons before they reach the collector. For the base current, the activation energy is also 1.4eV, which is close to the bandgap of GaAs, indicating that band-to-band recombination plays a dominant role in the base current. No trap-related recombination was observed for the base and collector currents, which further indicates the high quality carbon-doped GaAs base material for the HBT structures.

The Effect of Temperature and Si Concentration on the Mixing of AlAs/GaAs Superlattices

1986 ◽  
Vol 77 ◽  
Author(s):  
Ping Mei ◽  
H. W. Yoon ◽  
T. Venkatesan ◽  
S. A. Schwarz ◽  
J. P. Harbison
Keyword(s):  
Activation Energy ◽  
Molecular Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Length ◽  
Dopant Concentration ◽  
Effect Of Temperature ◽  
Surface Layers ◽  
Near Surface ◽  
Depth Profiles ◽  
Secondary Ion

ABSTRACTThe intermixing of AlAs/GaAs superlattices has been investigated as a function of Si concentration following anneals in the range of 500 to 900 C. The superlattice samples were grown by molecular beam epitaxy(MBE) and the near surface layers were doped with silicon at concentrations of 2×10 to 5×1018 cm-3. Si and Al depth profiles were measured with secondary ion mass spectrometry (SIMS).The diffusion length and activation energy of Al as a function of silicon dopant concentration are derived from the SIMS data. In the temperature range studied an activation energy for the Al interdiffusion of -4eV is observed with the diffusion coefficients increasing rapidly with Si concentration.

Narrow Si doping distributions in 6-doped GaAs, Al0.3Ga0.7As and Quantum Wells grown by Gas Source Molecular Beam Epitaxy

1989 ◽  
Vol 145 ◽  
Author(s):  
J.E. Cunningham ◽  
T.H. Chin ◽  
B. Tell ◽  
W. Jan ◽  
J. A. Ditzenberger ◽  
...  
Keyword(s):  
Activation Energy ◽  
Molecular Beam Epitaxy ◽  
Substrate Temperature ◽  
Quantum Wells ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Atomic Diffusion ◽  
Si Doping ◽  
Gas Source ◽  
Capacitance Voltage

AbstractWe report very small interdiffusion and surface segregation of Si in δ-doped GaAs, A10.3Gao.7As and Quantum Wells grown at 580 C by Gas Source Molecular Beam Epitaxy. Capacitance-Voltage profiles of δ-doped layers are 38 Å wide for growth at 580 C and further, insignificant profile narrowing is observed at 530C and below. Much wider profiles are observed at equivalent substrate temperature for As4 growth. Atomic diffusion of Si in δ-doped Al0.3Ga0.7As is found to have a rate of D0=5× 10−cm2/sec with an activation energy of 1.8 eV.

Stress Induced Lateral Concentration Profiles in SiGe Layers Grown on Si(001) Non-Planar Substrates

2001 ◽  
Vol 664 ◽  
Author(s):  
Anat Eshed ◽  
Robert Beserman ◽  
Klauss Dettmer
Keyword(s):  
Activation Energy ◽  
Diffusion Model ◽  
Molecular Beam ◽  
Substrate Thickness ◽  
Concentration Profiles ◽  
Lateral Variation ◽  
Composition Profiles ◽  
Stress Profiles ◽  
Planar Substrates ◽  
Good Agreement

ABSTRACTIn this paper we report lateral variation of Si and Ge concentration profiles measured in SiGe layers grown on mesa shaped Si(001) substrates. Si(001) substrate was patterned using conventional lithography process in forms of mesa with two crystal planes: (001) top plane and the etched (111) side plane. 50 nm thick Si0.7Ge0.3 strained epitaxial layer was grown using Molecular Beam Epitaxy (MBE), on top of the substrate. Thickness on the center of both crystal planes agrees with the expected values. Lateral image of composition profiles has been obtained from Micro Raman spectra taken at various locations on the mesa. Lower concentration of Ge was found at the vicinity of the edges of the (001) planes relative to the centers. We introduce a diffusion model using stress enhanced activation energy to explain our data, taking into account stress profiles along the mesas, by modifying the activation energy for planar diffusion model. The planar diffusion length was used as a fitting parameter in the model, with good agreement to known values from the literature.

The activation energy of the nitrogen acceptor in p-type ZnO film grown by plasma-assisted molecular beam epitaxy

2006 ◽  
Vol 140 (7-8) ◽  
pp. 345-348 ◽  
Author(s):  
J.W. Sun ◽  
Y.M. Lu ◽  
Y.C. Liu ◽  
D.Z. Shen ◽  
Z.Z. Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Zno Film ◽  
P Type

Temperature Dependence of morphology of InP Films Grown by metalorganic molecular Beam Epitaxy

1993 ◽  
Vol 317 ◽  
Author(s):  
M.A. Cotta ◽  
R.A. Hamm ◽  
S.N.G. Chu ◽  
L.R. Harriott ◽  
H. Temkin
Keyword(s):  
Activation Energy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Initial Conditions ◽  
Substrate Surface ◽  
Epitaxial Films ◽  
Kinetic Roughening ◽  
A Value ◽  
Metalorganic Molecular Beam Epitaxy ◽  
Increasing Temperature

ABSTRACTTwo regimes of growth are observed for epitaxial films of InP prepared by metalorganic molecular beam epitaxy. Below a minimum growth temperature, kinetic roughening is observed. At temperatures higher than smooth morphologies are obtained. From the dependence of on the substrate Misorientation, we estimate a value of ∼0.4–0.5eV for the Schwoebel barrier. At growth temperatures higher than we observe two types of defects: large oval defects related only to the initial conditions of the substrate surface and small defects with the density strongly dependent on the growth condition. Increasing temperature above or decreasing V/III ratio, results in increased density of these defects. In addition, their density increases with an activation energy that depends on the substrate Misorientation. The origin of the oval defects is attributed to non-stoichiometric, P-defficient, clusters on the growing surface, formed either by enhanced cracking of metalorganic s on the substrate due to the presence of contaminants or by a low V/III ratio used for growth.

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