UScholar Works
 
Filters: Department: "Materials Science & Engineering" Collection: "ir_uspace" Year End: 1996
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CreatorTitleDescriptionSubjectDate
1 Stringfellow, Gerald B.Atomic force microscopy study of ordered GaInPExamines the nature of the steps on the surface of gallium indium phosphide lattice layers matched to gallium arsenide substrates using atomic force microscopy. Temperatures of organometallic vapor phase epitaxy used; Relation of height of steps with misorientation angle; Link of supersteps with the...Surface chemistry; Lattice theory1995
2 Stringfellow, Gerald B.; Williams, Clayton C.Atomic ordering of GaInP studied by Kelvin probe force microscopyThe atomic ordering of GaInP has been established and studied by a variety of methods, including transmission electron microscopy, cathodoluminescence, and photoluminescence. In this work, a Kelvin probe force microscope _x0002_KPFM_x0003_ has been employed to image several GaInP samples previous...Cathodoluminescence; Photoluminescence; Surface morphology1995
3 Stringfellow, Gerald B.Control and characterization of ordering in GaInPGae,,In,,P layers have been grown by organometallic vapor phase epitaxy on GaAs substrates with [llO]-oriented grooves on the surface that have an important effect on the formation of Cu-Pt ordered structures during growth. In this work, the groove shape is demonstrated to be critically important...Vapor phase epitaxy; Ordered structure; Cathodoluminescence spectroscopy1993-06-28
4 Stringfellow, Gerald B.Control of ordering in Ga0.5In0.5P using growth temperatureThe kinetic processes leading to ordering in Gas,, In o.4P8 have been studied by observing the effects of substrate misorientation (O-9), growth rate (0.1-0.5), and substrate temperature (570- 670 "C) during growth. The ordered structure and degree of ordering are determined using transmission elec...Ordering Structure; Growth Temprature; Growth Rate1994
5 Stringfellow, Gerald B.Correlation between surface structure and ordering in GaInPGa and In atoms in Ga0.52In0.48P layers spontaneously segregate to form alternating In- and Ga-rich {111} monolayers during organometallic vapor phase epitaxial (OMVPE) growth on (001) oriented GaAs substrates, thus forming the CuPt ordered structure. This ordering phenomenon is believed to be drive...Transformations; Absorbtion spectra; Surface Properties1996
6 Stringfellow, Gerald B.Deep electron traps in organometallic vapor phase grown AlGaAsDeep electron traps have been studied by means of deep level transient spectrosocopy in type nominally undoped and interntionally te doped Al Ga As epitaxial layers which were grown by vapor phase epitaxy from organometallic compounds (OMVPE). Three main deep electron levels are present in undoped m...Vapor phase epitaxy; Shallow impurity identity; Optoelectronic device performance1980
7 Stringfellow, Gerald B.Dislocations in GaAs17-xPxDislocations, their origins, and their effects on photoluminescence efficiency have been studied in GaAs1-xPx single crystals grown by vapor phase epitaxy. Dislocations were observed using etch pit, optical-transmission microscopy, and x-ray topography techniques. Two types of dislocations are grown...Photoluminescence efficiency; Growth mechanism; Optical transmission microscopy1969
8 Stringfellow, Gerald B.Doping studies of Ga0.5In0.5P organometallic vapor-phase epitaxyPresents doping studies of gallium[sub0.5] indium[sub0.5] phosphorus organometallic vapor-phase epitaxy. Distribution coefficient of indium; Description of growth conditions; Case of poor growth morphology for gallium[sub0.5] indium[sub0.5] phosphorus.Phosphorus; Gallium; Doping1986
9 Stringfellow, Gerald B.Effect of oxygen incorporation in semi-insulating (AlxGa1-x)yIn1-yPDiscusses a study conducted on oxygen-doped, semi-insulating layers of (aluminum-gallium) indium phosphide grown on gallium arsenide using organometallic vapor phase epitaxy. Effect of oxygen doping on semi-insulating layers of the substance; Secondary-ion mass spectrometry measurements; Measured co...Inactive interstitial atoms; Energy-dispersive spectoscopy; intentional oxygen1992
10 Liu, FengEffect of size and dimensionality on the magnetic moment of transition metalsThe effect of size and dimensionality on the magnetic moments of Fe, Co, and Ni have been studied theoretically by confining the atoms t o various structural forms such as chains,surfaces, and thin films. The size of these systems is controlled by limiting t h e number of atoms. A new first-princip...Magnetic moment; Dimensionality; Size effects; Fe; Co; Ni1990
11 Stringfellow, Gerald B.Effect of step structure on ordering in GaInPExamines the effect of step structure on ordering in gallium indium phosphite (GaInP) using atomic force microscopy. Coverage of the surface by islands several monolayers in height with elongated direction; Formation of the edges of the islands; Role of the observations in explaining the nature of t...Gallium indium phosphite (GaInP); Twin boundaries1995-11-12
12 Stringfellow, Gerald B.Effects of substrate misorientation and growth rate on ordering in GaInPEpitaxial layers of Ga,Tn,_,P with 1=0.52 have been grown by-organometallic vapor-phase apitaxy on GaAs substrates misoriented from the (001) plane in the [ 1 IO] direction by angles 6,) of O", 3", 6", and 9". For each substrate orientation growth rates rg of 1, 2, and 4 pm/h have been used. The ...Transmission electron diffraction; Dark-field imaging; Photoluminescence1994
13 Stringfellow, Gerald B.Effects of V/III ratio on ordering in GaInP: atomic scale mechanismsGa0.5In0.5P layers have been grown by organometallic vapor-phase epitaxy using various values of input V/III ratio for two phosphorus precursors, phosphine, the conventional precursor, and tertiarybutylphosphine (TBP), a newly developed, less-hazardous precursor. For growth on nominally (001) GaAs s...Photoabsorption spectroscopy; Transmission electron diffraction; Phosphorus precursor1996-05-01
14 Stringfellow, Gerald B.Electrical properties of nitrogen doped GaPThe electrical properties namely, electron concentration and mobility, have been investigated in the temperature range from 53 to 400 K for undoped and nitrogen-doped VPE GaP.Electron concentration; Ionization energy; Electron mobility1975
15 Stringfellow, Gerald B.Electron mobility in AlxGa1-xAshe electron mobility in AlxGa1-xAs grown by several techniques has been studied to determine whether VPE layers are more highly compensated than comparable LPE layers. The techniques used to grow layers included (1) organometallic VPE using Al(CH3)3, AsH3, and Ga(C2H5)3 or Ga(CH3)3, (2) ''hybrid'' o...Alloys; Organometallics1979-06
16 Stringfellow, Gerald B.Electron mobility in compensated GaAs and AlGaAsThe dependence of electron mobility on temperature in GaAs and Al Ga As indicates that for cimpensated material a term having causes a significant reduction in the mobility measured at high temperatures. The magnitude of the term in mobility, denoted is found to be linearly proportional to the compe...Unspecified mobility; Reduced mobility; Space charge regions1980
17 Liu, FengElectronic and elastic properties of edge dislocations in SiAb initio, tight-binding, and classical calculations have been done for (a/2)( 110) edge dislocation dipoles in Si at separations of 7.5-22.9 A in unit cells comprising 32-288 atoms. These calculations show states associated with the cores relatively deep in the band gap (~ 0.2 eV) despite the abse...Edge dislocations1995-06
18 Liu, FengFirst-principles studies on structural properties of β-cristobaliteThe structure of β-cristobalite has been studied through a first-principles total-energy minimization in the local-density approximation using a Car-Parrinello-type algorithm combined with the Vanderbilt ultrasoft pseudopotential scheme. It was found that the hypothetical ordered structure propose...First-principles; Car-Parrinello-type algorithm1993-05
19 Liu, FengFirst-principles study of crystalline silicaWe have investigated the structural properties of five different crystalline forms of Si02 using a first-principles approach. An ultrasoft Vanderbilt pseudopotential is generated for oxygen which enables us to use a small plane-wave cutoff of 25 Ry. The relative stability, the equation of state, an...First-principles; Crystalline silica; Ultrasoft Vanderbilt pseudopotential1994-05
20 Stringfellow, Gerald B.GaInAsSb metastable alloys grown by organometallic vapor phase epitaxyGa1-xlnx As1-ySby alloys have been grown by organometallic vapor phase epitaxy using trimethyl compounds of Ga, In, As, and Sb(TMGa, TMIn, TMAs, and TMSb) plus AsH3 in an atmospheric pressure, horizontal, infrared heated reactor. For the first time, alloys near the center of the region of solid immi...Organometallic; Alloys; Vapor phase epitaxy1986
21 Stringfellow, Gerald B.InAsSbBi alloys grown by organometallic vapor-phase epitaxyProvides information on a study on the growth of InAsSbBi alloys by organometallic vapor-phase epitaxy. Experiment; Results and discussion; Conclusion.Alloys; Epitaxy; Organometallic Compounds1994
22 Liu, FengInterplay of stress, structure, and stoichiometry in Ge-covered Si(001)By calculating the evolution of surface energies and surface stress tensors of Ge-covered Si(001) with increasing Ge coverage, we derive the most probable Ge stoichiometry in the subsurface regions beyond 1 monolayer coverage. We compare the calculated surface reconstruction and surface stress at th...Ge-covered; Si(001); Stress; Structure; Surface stress tensors1996-04
23 Stringfellow, Gerald B.Kinetically controlled order/disorder structure in GaInPA Ga0.52In0.58p order/disorder heterostructure having a band-gap energy difference exceeding 160 meV has been grown by organometallic vapor phase epitaxy. The two layers were grown on a nominally (OOl)-oriented GaAs substrate misoriented by 3° toward the [110] direction in the lattice. The disorder...Indium phosphides; Gallium Phosphides; Heterojunctions1994
24 Liu, FengLiu et al replyIn our Letter [1], we have demonstrated the plausibility of a structure for ?-cristobalite SiC2 consisting of domains of I Aid symmetry, and provided strong evidence against other proposed models, based on first-principles total energy and lattice dynamics calculations. We are pleased that the Auth...beta-Cristobalite SiO2; Rigid unit modes; RUM; Transient domain formation1993
25 Liu, FengLiu et al. replyIn our paper we were alluding to a structural phase transition rather than an order-disorder one. We agree with Blaschko2 that more work needs to be done regarding the statistical mechanics of the hydrogen ordering. This was already acknowledged in our paper when we stated that the model of nonint...Structural phase transition; Hydrogen ordering; Ising lattice-gas models; Proton glass1990
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