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1 Jan 1990

Volume 56, Issue 1, pp. 1-100

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Logic inverter based on side mode injection locking in semiconductor lasers

J. G. Provost and R. Frey

Appl. Phys. Lett. 56, 1 (1990); http://dx.doi.org/10.1063/1.102650 (3 pages) | Cited 5 times

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The performance of a logic inverter based on injection locking in laser diodes is presented. The fast commutation rise and fall times (5 and 2 ns, respectively) allow a 150 MHz repetition rate. Due to the gain existing in laser diodes, low optical switching energies (50 fJ) and large fan‐out rates (30) are also obtained, making such an inverter attractive for the purpose of parallel optical computing, particularly if semiconductor laser arrays are used in place of single laser diodes.
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42.79.Ta Optical computers, logic elements, interconnects, switches; neural networks
42.55.Px Semiconductor lasers; laser diodes
42.65.Pc Optical bistability, multistability, and switching, including local field effects

Binary‐optics miniature Talbot cavities for laser beam addition

J. R. Leger and M. P. Griswold

Appl. Phys. Lett. 56, 4 (1990); http://dx.doi.org/10.1063/1.102644 (3 pages) | Cited 2 times

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A miniature external cavity has been fabricated from a single 4.5 mm substrate for coherent beam addition of a linear AlGaAs laser array. Binary‐optics elements are fabricated on the front surface for laser beam collimation and onto the back surface for lateral mode selection. Near‐diffraction‐limited performance has been observed with up to 80% of the far‐field power contained in the central lobe.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems
42.15.Eq Optical system design
42.79.Bh Lenses, prisms and mirrors
42.55.Px Semiconductor lasers; laser diodes

Self‐mode‐locking of a semiconductor laser using positive feedback

D. J. Derickson, R. J. Helkey, A. Mar, P. A. Morton, and J. E. Bowers

Appl. Phys. Lett. 56, 7 (1990); http://dx.doi.org/10.1063/1.102658 (3 pages) | Cited 4 times

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A new mode‐locking technique, self‐mode‐locking, is described which uses the detected optical pulses from the mode‐locked laser as the active driving source. This technique forms narrow‐width mode‐locked optical pulses at low repetition rates without the use of a microwave synthesizer.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes

Gain characteristics of strained quantum well lasers

D. F. Welch, W. Streifer, C. F. Schaus, S. Sun, and P. L. Gourley

Appl. Phys. Lett. 56, 10 (1990); http://dx.doi.org/10.1063/1.102647 (3 pages) | Cited 37 times

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InGaAs/AlGaAs laser diode arrays fabricated with differing amounts of In in the quantum well active layer are characterized by threshold currents of 115 A/cm2, transparency currents of 50 A/cm2, optical losses of 3 cm−1, and wavelengths to 960 nm for In compositions of 20%. Gain coefficient measurements indicate an increase from 0.0535 to 0.0691 cm μm/A for quantum well lasers with 0% InAs and 10–20% InAs, respectively. The maximum output power achieved for a device with a 100 μm aperture is 3 W cw.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
78.45.+h Stimulated emission

Fabrication of channel waveguides in polydiacetylenes: Composite diffused glass/polymer structures

N. E. Schlotter, J. L. Jackel, Paul D. Townsend, and Gregory L. Baker

Appl. Phys. Lett. 56, 13 (1990); http://dx.doi.org/10.1063/1.102648 (3 pages) | Cited 20 times

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We report the fabrication of single‐mode channel waveguides in spun films of polydiacetylenes using an inverted rib design. These robust guides consist of a planar layer of the polydiacetylene spun on a glass substrate in which high‐index channels have been defined by ion exchange. Models of such guides show that most of the optical field of the guided wave is confined to the polymer layer, with the high‐index glass channels providing lateral confinement. End‐fire coupling of 1.06, 1.15, 1.32, and 1.55 μm light into the composite guides resulted in single‐mode guiding with the light confined to the polymer layer. This approach to waveguide formation should be applicable to a wide range of polymeric materials.
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42.79.Gn Optical waveguides and couplers
42.82.-m Integrated optics
78.66.Qn Polymers; organic compounds

Demonstration of a grating‐surface‐emitting diode laser with low‐threshold current density

N. W. Carlson, G. A. Evans, D. P. Bour, and S. K. Liew

Appl. Phys. Lett. 56, 16 (1990); http://dx.doi.org/10.1063/1.102649 (3 pages) | Cited 7 times

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This letter reports the demonstration of grating‐surface‐emitting (GSE) lasers with threshold current densities as low as 440 A/cm2. When the distributed‐Bragg‐reflector sections were cleaved from these lasers, the resulting edge‐emitting lasers had threshold current densities that were essentially unchanged from that of the GSE laser. However, the operating wavelength of the Fabry–Perot laser was typically 70 Å shorter than that of the surface emitter.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Fc Modulation, tuning, and mode locking
42.50.-p Quantum optics

TE/TM mode selective channel waveguides in GaAs/AlAs superlattice fabricated by SiO2 cap disordering

Yasuhiro Suzuki, Hidetoshi Iwamura, and Osamu Mikami

Appl. Phys. Lett. 56, 19 (1990); http://dx.doi.org/10.1063/1.103274 (2 pages) | Cited 19 times

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Novel structure TE/TM mode selective optical channel waveguides are proposed and fabricated in GaAs/AlAs superlattices (SLs) using impurity‐free disordering induced by SiO2 cap annealing. The disordered SL regions are found to be useful as low‐loss waveguides even at a wavelength close to the absorption edge of the as‐grown SL. By observing the near‐field patterns, it is confirmed that these channel waveguides could selectively confine TE or TM polarized light.
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42.79.Gn Optical waveguides and couplers
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Plasma oxidation of SO2

I. Sardja and S. K. Dhali

Appl. Phys. Lett. 56, 21 (1990); http://dx.doi.org/10.1063/1.102651 (3 pages) | Cited 21 times

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We report the results of an experimental investigation of plasma‐assisted oxidation of SO2 to SO3. A coaxial dielectric‐barrier discharge is used to generate atomic oxygen to carry out the reaction. The dielectric‐barrier discharge, which is an interrupted discharge, is very efficient in producing atomic oxygen and requires a simple form of excitation. We have observed a significant reduction (up to 90%) in the SO2 concentration using this technique. The results of varying the gas composition, the gas pressure, and the gas flow are also reported.
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81.05.Kf Glasses (including metallic glasses)
81.65.-b Surface treatments
52.80.Hc Glow; corona

Concentration dependence and interfacial instabilities during ion beam annealing of arsenic‐doped silicon

Francesco Priolo, Emanuele Rimini, Corrado Spinella, and Giuseppe Ferla

Appl. Phys. Lett. 56, 24 (1990); http://dx.doi.org/10.1063/1.102635 (3 pages) | Cited 1 time

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Ion beam induced epitaxy of amorphous Si layers onto 〈100〉 substrates has been investigated by varying the As concentration. At As concentrations below 4×1018/cm3 no rate effect is observed. In the intermediate regime, between 4×1018/cm3 and 2×1021/cm3, the growth rate increases linearly with the logarithm of As concentration and reaches a value about a factor of 2 higher than that of intrinsic Si. At concentrations above 2×1021/cm3, the epitaxy experiences a sudden, severe retardation. Finally, at a concentration of ∼6×1021/cm3, twins are observed to form.
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61.80.Jh Ion radiation effects
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.35.B- Structure of clean surfaces (and surface reconstruction)

Analysis for dislocation density reduction in selective area grown GaAs films on Si substrates

Masafumi Yamaguchi, Masami Tachikawa, Mitsuru Sugo, Susumu Kondo, and Yoshio Itoh

Appl. Phys. Lett. 56, 27 (1990); http://dx.doi.org/10.1063/1.102636 (3 pages) | Cited 33 times

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High quality GaAs films with dislocation densities of less than 1×106 cm−2 on (100) Si substrates have been obtained by selective area growth using the metalorganic chemical vapor deposition method. Remarkable reduction of residual stress and dislocation density in the GaAs layers due to selective area growth have been analyzed using a simple model, in which the assumptions are that the generation of dislocations is caused by thermal stress in the films and dislocation density reduction in GaAs films on Si due to selective growth is caused by stress relief.
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61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology

Grain boundary mediated amorphization in silicon during ion irradiation

Harry A. Atwater and Walter L. Brown

Appl. Phys. Lett. 56, 30 (1990); http://dx.doi.org/10.1063/1.102637 (3 pages) | Cited 18 times

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Amorphous Si is nucleated heterogeneously at grain boundaries during irradiation of polycrystalline Si thin films by 1.5 MeV Xe+ ions for temperatures of 150–225 °C. Moreover, the heterogeneous nucleation kinetics of amorphous Si are strongly dependent on grain boundary structure. Following formation at grain boundaries, the amorphous Si layer grows at a rate comparable to that previously observed at a pre‐existing planar amorphous‐crystal interface. As amorphization proceeds, a decrease in average grain size and a marked change in the grain size distribution results. We suggest a simple atomistic model for amorphous phase formation in Si in which the nucleation kinetics are dependent on the point defect‐grain boundary interactions.
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61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.05.Rm Porous materials; granular materials

Electrical and optical evidence of resonant tunneling of holes in an n+in+ double‐barrier diode structure under illumination

N. Vodjdani, D. Côte, D. Thomas, B. Sermage, P. Bois, E. Costard, and J. Nagle

Appl. Phys. Lett. 56, 33 (1990); http://dx.doi.org/10.1063/1.102638 (3 pages) | Cited 23 times

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Using low‐temperature photocurrent, steady‐state and time‐resolved photoluminescence, we have shown the importance of hole transport in the optical properties of n+in+ double‐barrier diodes under operation. We have also seen evidence of resonant tunneling of minority holes in such an illuminated double‐barrier diode.
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85.30.Hi Surface barrier, boundary, and point contact devices
73.50.-h Electronic transport phenomena in thin films
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
73.40.Gk Tunneling

Observation of AlGaAs/GaAs multiquantum well structure by scanning tunneling microscopy

J. M. Gómez‐Rodríguez, A. M. Baró, J. P. Silveira, M. Vázquez, Y. González, and F. Briones

Appl. Phys. Lett. 56, 36 (1990); http://dx.doi.org/10.1063/1.102639 (3 pages) | Cited 9 times

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We have imaged an AlGaAs/GaAs multiquantum well structure by scanning tunneling microscopy (STM). In order to localize the structure the STM is integrated in a conventional scanning electron microscope. The observed surface structure has a periodicity of ≊180 Å and shows an apparent corrugation of ≊10 Å in the constant current mode. We discuss the possible mechanisms of the observed contrast, which we tentatively attribute to the different electrical properties of the two different layers.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination
68.35.B- Structure of clean surfaces (and surface reconstruction)
07.78.+s Electron, positron, and ion microscopes; electron diffractometers

Morphology and distribution of atomic steps on Si (001) studied with scanning tunneling microscopy

D. Dijkkamp, A. J. Hoeven, E. J. van Loenen, J. M. Lenssinck, and J. Dieleman

Appl. Phys. Lett. 56, 39 (1990); http://dx.doi.org/10.1063/1.102640 (3 pages) | Cited 30 times

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We have studied the morphology and distribution of atomic steps on Si(001) with scanning tunneling microscopy. We find that native oxide removal at temperatures up to 1350 K leads to step pinning and bunching. Cleaning at temperatures above 1450 K leads to regular step distributions which reflect the macroscopic misorientation of the sample. Steps running parallel to the 2×1 dimer rows on the upper terrace are straight, whereas steps perpendicular to these rows are ragged.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
81.65.-b Surface treatments
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination
68.35.Dv Composition, segregation; defects and impurities

Study of the interface of undoped and p‐doped ZnSe with GaAs and AlAs

L. Kassel, H. Abad, J. W. Garland, P. M. Raccah, J. E. Potts, M. A. Haase, and H. Cheng

Appl. Phys. Lett. 56, 42 (1990); http://dx.doi.org/10.1063/1.102641 (3 pages) | Cited 27 times

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We have used electrolyte electroreflectance (EER) to characterize ZnSe/GaAs and ZnSe/AlAs interfaces. The great sensitivity of EER to interface space‐charge regions enabled us to detect both interface crossover transitions and transitions to triangular‐well interface states. The observation of these transitions provides the first unambiguous proof that the ZnSe/GaAs interface is type I and allowed us to determine the band offsets and band bendings, the diffusion lengths across each interface, and the amount of interdiffusion.
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73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
68.35.Fx Diffusion; interface formation

Characterization of strained InGaAs single quantum well structures by ion beam methods

Kin Man Yu and K. T. Chan

Appl. Phys. Lett. 56, 45 (1990); http://dx.doi.org/10.1063/1.102642 (3 pages) | Cited 9 times

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We have investigated strained InGaAs single quantum well structures using MeV ion beam methods. The structural properties of these structures, including composition and well size, have been studied. It has been found that the composition obtained by Rutherford backscattering spectrometry and particle‐induced x‐ray emission techniques agrees very well with that obtained by the ion channeling method.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.Nq Composition and phase identification
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Carrier capture in intermixed quantum wires with sharp lateral confinement

H. Leier, A. Forchel, B. E. Maile, G. Mayer, J. Hommel, G. Weimann, and W. Schlapp

Appl. Phys. Lett. 56, 48 (1990); http://dx.doi.org/10.1063/1.102643 (3 pages) | Cited 34 times

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We have fabricated GaAs/GaAlAs quantum wires with widths between 220 and 40 nm by high‐dose (2×1014 cm−2) Ga implantation in a locally masked single quantum well structure. The width dependence of the emission energies indicates a steep 1D confinement determined by the lateral straggling of the implanted Ga. The external quantum efficiency of the wires increases strongly with decreasing mask width due to significant carrier capture from the lateral barrier.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Reduction in misfit dislocation density by the selective growth of Si1−xGex/Si in small areas

D. B. Noble, J. L. Hoyt, C. A. King, J. F. Gibbons, T. I. Kamins, and M. P. Scott

Appl. Phys. Lett. 56, 51 (1990); http://dx.doi.org/10.1063/1.103176 (3 pages) | Cited 50 times

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Si1−xGex and Si layers have been grown selectively in the exposed Si regions on oxide‐patterned 〈100〉 oriented Si wafers using the chemical vapor deposition technique limited reaction processing. Misfit dislocation spacings at the heterointerface were measured using plan‐view transmission electron microscopy in conjunction with a large‐area thinning technique which allows for examination of 100–150 μm diameter areas. The dislocation density is reduced by at least a factor of 20 for small areas (lateral dimensions: tens of microns) bounded by oxide isolation when compared to adjacent large areas (millimeters) which are uninterrupted by the patterned oxide. The ability to selectively grow Si1−xGex on patterned wafers and the area‐dependent reduction in dislocation density in as‐grown films may be important considerations for future device applications using Si1−xGex strained layers.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.65.-b Surface treatments
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.35.Dv Composition, segregation; defects and impurities

Misfit dislocation multiplication processes in Si1−xGex alloys for x<0.15

C. G. Tuppen, C. J. Gibbings, M. Hockly, and S. G. Roberts

Appl. Phys. Lett. 56, 54 (1990); http://dx.doi.org/10.1063/1.102645 (3 pages) | Cited 23 times

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The density of misfit dislocation sources in strained Si1−xGex layers grown on Si substrates is rarely sufficient to explain the observed extent of relaxation when layer thicknesses are in excess of the metastable critical thickness. This letter describes a process whereby a small, but finite number of misfit dislocation nucleation sources can lead to extensive strain relaxation across a complete wafer. Two novel mechanisms for misfit dislocation multiplication are presented and shown to be compatible with microscopic observations of chemically etched layers.
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61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.55.-a Thin film structure and morphology
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Cyclotron resonance measurements of the high electron mobility transistor

Chian‐Sern Chang, Harold R. Fetterman, and Arold Green

Appl. Phys. Lett. 56, 57 (1990); http://dx.doi.org/10.1063/1.103184 (3 pages)

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The photoconductivity cyclotron resonance measurement is used to determine the effective masses of the high electron mobility transistor. The experimental data show that the effective mass is a function of the gate voltage.
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85.30.Tv Field effect devices
85.30.De Semiconductor-device characterization, design, and modeling
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.50.Pz Photoconduction and photovoltaic effects

Variable resonator (variable Q) photopumped phonon‐assisted quantum well laser operation

N. Holonyak, D. W. Nam, E. J. Vesely, L. J. Guido, P. Gavrilovic, K. Meehan, W. Stutius, and J. E. Williams

Appl. Phys. Lett. 56, 60 (1990); http://dx.doi.org/10.1063/1.102646 (3 pages) | Cited 4 times

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Data are presented on a photopumped rectangular (w=40 μm, l=250 μm) quantum well heterostructure (QWH), with variable resonator Q along the sample, showing that phonon‐assisted laser operation predominates. To achieve variable resonator Q, the QWH sample is heat sunk embedded in In over half of its length (reflecting edges, high Q), as opposed to simple contact with a Au shim over the remaining half and no reflecting metal on the sample edges (low Q). Photopumping at the low Q, high Q boundary near the sample center turns on and off the n=1 confined‐particle recombination transition (E11 ) and sets a higher energy experimental (as well as calculated) reference, ℏω2 =E11, for the lower energy phonon‐assisted laser operation, ℏω1 =E11 −ℏωLO .
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
78.45.+h Stimulated emission

Hydrogen‐accelerated thermal donor formation in Czochralski silicon

H. J. Stein and S. K. Hahn

Appl. Phys. Lett. 56, 63 (1990); http://dx.doi.org/10.1063/1.102652 (3 pages) | Cited 36 times

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Acceleration of thermal donor formation at 400 °C in Czochralski Si by a hydrogen plasma has been observed using low‐temperature infrared absorption and spreading resistance probe measurements. The accelerated formation in as‐grown Si is attributed to hydrogen diffusion and catalyzed conversion of electrically inactive nuclei to thermal donors. When the nuclei concentration is small such as in rapid thermal annealed Si, hydrogen interaction at SiO bonds is suggested as the rate‐limiting step in thermal donor formation.
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78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
61.72.Bb Theories and models of crystal defects
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Rapid thermal oxidation of GeSi strained layers

D. Nayak, K. Kamjoo, J. C. S. Woo, J. S. Park, and K. L. Wang

Appl. Phys. Lett. 56, 66 (1990); http://dx.doi.org/10.1063/1.102653 (3 pages) | Cited 61 times

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The experimental results of the rapid thermal oxidation in the initial oxidation regime of molecular beam epitaxy grown GeSi strained layers are reported. It is shown that the dry oxidation rate of GeSi is the same as that of Si at different temperatures. After a very short initial time (∼10 s), the oxide thickness appears to be a linear function of time, which suggests that the kinetics of oxide growth during dry oxidation is limited by surface reaction controlled mechanisms. Further, the oxidation rate in the thin oxide regime is not affected by the Ge content up to 20% in the GeSi strained layer for dry oxidation. Using secondary‐ion mass spectrometry, it is found that Ge is completely rejected out of the SiO2 layer which is formed during oxidation, and a Ge‐rich layer is formed at the SiO2/GeSi interface. A significant amount of Ge is found to diffuse into the underlying GeSi layer during the growth of thin oxide films.
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81.65.-b Surface treatments
68.35.Fx Diffusion; interface formation
85.40.Hp Lithography, masks and pattern transfer
68.55.-a Thin film structure and morphology

Metal/(100) GaAs interface: Case for a metal‐insulator‐semiconductor‐like structure

J. L. Freeouf, J. M. Woodall, L. J. Brillson, and R. E. Viturro

Appl. Phys. Lett. 56, 69 (1990); http://dx.doi.org/10.1063/1.102654 (3 pages) | Cited 20 times

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Various models have been developed to address the problem of ‘‘Fermi level pinning,’’ i.e., why the barrier height varies much less than the Schottky metal work function limit. The most widely accepted mechanism is some variant of the metal‐induced gap state model. However, recent experimental data on (100)InxGa1−x As surfaces and interfaces (0≤x≤1) suggest that the surface or interface Fermi level can assume values which lie well outside the variance associated with Fermi level pinning; in fact, recent data suggest the achievement of the Schottky limit. Furthermore, studies of epitaxially grown layers where dopant incorporation is dependent on an interface Fermi level suggest that such Fermi level positions are not always pinned. In order to account for these recent results, along with the pinned values, we introduce the concept of an insulating layer like surface reconstruction. Recent calculations suggest that reconstructions of the GaAs(100) surface are insulating. Thus, we suggest that the GaAs(100) metal interface is often a metal (M)/surface reconstruction layer (I)/GaAs bulk (S), or MIS‐like. This approach attempts to reconcile disparate models of interface behavior by showing the limits of validity of these models with respect to the actual physical structure of the interface in question.
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73.30.+y Surface double layers, Schottky barriers, and work functions
73.20.At Surface states, band structure, electron density of states
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
68.35.B- Structure of clean surfaces (and surface reconstruction)

Growth of InGaAs/InAlAs quantum wells on InP patterned substrates by molecular beam epitaxy

F. S. Turco, M. C. Tamargo, D. M. Hwang, R. E. Nahory, J. Werner, K. Kash, and E. Kapon

Appl. Phys. Lett. 56, 72 (1990); http://dx.doi.org/10.1063/1.102655 (3 pages) | Cited 9 times

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We have grown InGaAs/InAlAs quantum wells and InGaAs, InAlAs single layers over InP nonplanar substrates. Photoluminescence, transmission electron microscopy, and energy‐dispersive x‐ray analysis give evidence for large lateral thickness and compositional variations, which lead to in situ modification of the growth profile. These effects, which differ for InGaAs and InAlAs, reveal the importance of surface migration in (Al,Ga)InAs. Our results demonstrate a tool for in situ lateral patterning of this material system.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.35.Fx Diffusion; interface formation
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Nq Composition and phase identification
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