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21 Jul 1986

Volume 49, Issue 3, pp. 119-182


Optically pumped tunable mode‐locked Si‐doped GaAs laser

B. Valk, T. S. Call, M. M. Salour, W. Kopp, and H. Morkoç

Appl. Phys. Lett. 49, 119 (1986); http://dx.doi.org/10.1063/1.97197 (3 pages) | Cited 3 times

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Mode‐locked operation of Si‐doped bulk GaAs in external cavity was achieved by synchronous pumping with a Kr+ laser at 647.1 nm. High beam quality and peak powers of up to 3.3 W are unique features of this laser. The spontaneous spectrum is narrower than those of dyes, allowing a stabilized single‐frequency operation with fewer wavelength selective elements, while tunability over a range of 300 Å was achieved by varying the temperature.
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42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

High‐efficiency, high‐energy operation of an intense electron beam initiated HF chemical laser using a mixture containing a heavy fluoride MoF6

Hirohito Inagaki, Akira Suda, and Minoru Obara

Appl. Phys. Lett. 49, 122 (1986); http://dx.doi.org/10.1063/1.97198 (3 pages) | Cited 2 times

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High‐efficiency and high‐energy operation of HF chemical lasers was simultaneously realized using a low pressure mixture of H2/F2/O2/MoF6 initiated by an intense electron beam. The addition of small amounts of MoF6 gas to the mixture of H2/F2/O2 resulted in an increase in laser output energy and electrical and chemical efficiencies. A HF laser energy obtained from a mixture containing 17.9 Torr of MoF6 was 3.7 kJ (136 J/l) with a pulse width of 190 ns full width at half‐maximum. The corresponding electrical efficiency and chemical efficiency are 189% and 15.2%, respectively, with a low pressure (362.4 Torr) mixture of H2/F2/O2/MoF6=30/242/72.5/17.9 Torr.
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42.55.Ks Chemical lasers
78.60.Ps Chemiluminescence
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Narrowband grating resonator filters in InGaAsP/InP waveguides

R. C. Alferness, C. H. Joyner, M. D. Divino, M. J. R. Martyak, and L. L. Buhl

Appl. Phys. Lett. 49, 125 (1986); http://dx.doi.org/10.1063/1.97199 (3 pages) | Cited 35 times

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We report the first demonstration of efficient narrowband optical wavelength filters using InGaAsP/InP passive waveguide grating resonators. Filter bandwidths as narrow as 1 Å, centered about λ=1.55 μm with excess resonator loss as low as 1 dB, have been achieved.
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42.79.Ci Filters, zone plates, and polarizers
42.79.Gn Optical waveguides and couplers
07.60.-j Optical instruments and equipment
42.79.-e Optical elements, devices, and systems
42.79.Dj Gratings

Frequency response of an InGaAsP vapor phase regrown buried heterostructure laser with 18 GHz bandwidth

R. Olshansky, V. Lanzisera, C. B. Su, W. Powazinik, and R. B. Lauer

Appl. Phys. Lett. 49, 128 (1986); http://dx.doi.org/10.1063/1.97620 (3 pages) | Cited 10 times

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The frequency response of a 1.3‐μm InGaAsP vapor phase regrown buried heterostructure laser with an 18‐GHz cw bandwidth is analyzed in detail. The intrinsic bandwidth of the device is shown to be 22 GHz and the 3‐dB RC roll‐off frequency due to electrical parasitics is found to be 10 GHz.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.55.Px Semiconductor lasers; laser diodes

Self‐mode locking in a transverse‐discharge copper‐vapor laser

Kiegon Im and Jin J. Kim

Appl. Phys. Lett. 49, 131 (1986); http://dx.doi.org/10.1063/1.97200 (2 pages) | Cited 5 times

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A new observation of the self‐mode‐locking behavior of the copper‐vapor laser is reported. In the present experiment, self‐mode locking is observed for both of the 510.6‐nm and 578.2‐nm laser lines in a transverse‐discharge copper‐vapor laser. The conditions under which the self‐locking behavior is observed are at variance from previous results, but they are consistent with the generally accepted requirements. The self‐locking mechanism of the longitudinal modes is explained and a numerical comparison is made with a theory based on the third order polarization.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Lt Gas lasers including excimer and metal-vapor lasers

Highly efficient, long lived AlGaAs lasers fabricated by silicon impurity induced disordering

R. L. Thornton, R. D. Burnham, T. L. Paoli, N. Holonyak, and D. G. Deppe

Appl. Phys. Lett. 49, 133 (1986); http://dx.doi.org/10.1063/1.97201 (2 pages) | Cited 9 times

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The process of silicon impurity induced disordering has been used to fabricate very efficient buried heterostructure AlGaAs lasers with lifetimes in the thousands of hours at 50 °C. These devices operate in a single transverse mode up to 25 mW, and in a single longitudinal mode with adjacent mode suppression of 23 dB.
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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

Electroabsorption in an InGaAs/GaAs strained‐layer multiple quantum well structure

T. E. Van Eck, P. Chu, W. S. C. Chang, and H. H. Wieder

Appl. Phys. Lett. 49, 135 (1986); http://dx.doi.org/10.1063/1.97202 (2 pages) | Cited 47 times

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Electroabsorption in an InGaAs/GaAs strained‐layer multiple quantum well structure has been observed. With only ten quantum wells, 6.4% transmission modulation was obtained at 0.950 μm with 2 V reverse bias. A single absorption peak was observed, in contrast to the double peak observed in similar GaAs/AlGaAs structures. The present structure is fabricated on a GaAs substrate which is transparent to light at the exciton absorption wavelength.
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78.20.Jq Electro-optical effects
75.20.Ck Nonmetals
42.79.Hp Optical processors, correlators, and modulators

Photothermal modulation of the gap distance in scanning tunneling microscopy

Nabil M. Amer, Andrew Skumanich, and Dean Ripple

Appl. Phys. Lett. 49, 137 (1986); http://dx.doi.org/10.1063/1.97203 (3 pages) | Cited 38 times

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We have employed the photothermal effect to modulate the gap distance in a tunneling microscope. In this approach, optical heating induces the expansion and buckling of laser‐illuminated sample surface. The surface displacement can be modulated over a wide frequency range, and its height (typically <1 Å) can be varied by changing the illumination intensity and modulation frequency. This novel method provides an alternative means for performing tunneling spectroscopy and microscopy, and for determining work functions of materials.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
73.30.+y Surface double layers, Schottky barriers, and work functions

New approach to the high quality epitaxial growth of lattice‐mismatched materials

Serge Luryi and Ephraim Suhir

Appl. Phys. Lett. 49, 140 (1986); http://dx.doi.org/10.1063/1.97204 (3 pages) | Cited 158 times

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We have reconsidered the problem of the critical layer thickness hc for growth of strained heterolayers on lattice‐mismatched substrates, using a new approach which allows us to determine the spatial distribution of stresses in a bi‐material assembly and include the effects of a finite size of the sample. The possibility of dislocation‐free growth of lattice‐mismatched materials on porous silicon substrates is discussed as an example of a more general problem of heteroepitaxial growth on small seed pads of lateral dimension l, having a uniform crystal orientation over the entire substrate wafer. It turns out that for a given mismatch f, the critical film thickness hlc strongly depends on l, rising sharply when the latter is sufficiently small, l≲lmin. The characteristic size lmin( f ) below which, effectively, hlc( f )→∞, is determined in terms of the experimentally known (or calculated for growth on a monolithic substrate) function h∞c( f )≡hc( f ). When l≲lmin, then the entire elastic stress in the epitaxial film will be accommodated without dislocations.
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81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.60.Bs Mechanical and acoustical properties
68.55.-a Thin film structure and morphology

Stress relaxation technique for thermally grown SiO2

L. M. Landsberger and W. A. Tiller

Appl. Phys. Lett. 49, 143 (1986); http://dx.doi.org/10.1063/1.97205 (3 pages) | Cited 10 times

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A corona discharge technique has been utilized at 800 °C to fully relax thermal oxides grown on Si wafers. In an experiment involving two oxidation steps, the corona‐relaxed oxides are shown to be equivalent to ∼1200 °C thermally grown or thermally relaxed oxides, both with respect to index of refraction and oxygen diffusion coefficient. The activation energy for oxygen diffusion through a completely relaxed thermal oxide is found to be 0.8 eV.
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81.65.-b Surface treatments
81.40.Gh Other heat and thermomechanical treatments
75.20.Ck Nonmetals
68.35.Fx Diffusion; interface formation

Formation of amorphous alloys by the mechanical alloying of crystalline powders of pure metals and powders of intermetallics

Ricardo B. Schwarz and Carl C. Koch

Appl. Phys. Lett. 49, 146 (1986); http://dx.doi.org/10.1063/1.97206 (3 pages) | Cited 280 times

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Amorphous powders of Ni32Ti68 and of Ni45Nb55 were synthesized by mechanical alloying (MA) starting from either a mixture of pure metal powders (in the appropriate molar ratio) or from powders of the crystalline intermetallics NiTi2 and Ni45Nb55, respectively. For both alloys, the peak temperature increase (above the average processing temperature) in the powder particles trapped between colliding balls is estimated at 38 K. Thus, the amorphization is attributed to a process other than the formation of local melts followed by the rapid solidification of these melts into the amorphous phase. The amorphization by MA starting from a mixture of pure crystalline powders is attributed to a solid state interdiffusion reaction, the kinetics of which is controlled by the excess point and lattice defects generated by plastic deformation. The amorphization by MA starting from powders of crystalline intermetallics is attributed to the accumulation of point and lattice defects which raise the free energy of the faulted intermetallic above that of the amorphous alloy.
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81.05.Bx Metals, semimetals, and alloys
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
81.05.Kf Glasses (including metallic glasses)
66.30.Ny Chemical interdiffusion; diffusion barriers

Reverse‐bias current‐electric field characteristics of amorphous silicon films with blocking layers: Thickness dependence

H. Kakinuma, S. Nishikawa, T. Watanabe, and K. Nihei

Appl. Phys. Lett. 49, 149 (1986); http://dx.doi.org/10.1063/1.97207 (3 pages) | Cited 2 times

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Static current‐electric field (J‐F) characteristics of p‐type hydrogenated amorphous Si (a‐Si:H)/intrinsic (i) a‐Si:H/amorphous Si1−xCx structures under reverse‐biased conditions have been studied. These structures are widely used for xerographic photoreceptors. The main variable was the thickness of the i layer (di), ranging from 2.5 to 27 μm. The J‐F characteristics exhibited three distinct regions, i.e., an Ohmic region, a differential negative resistance (DNR) region, and a superlinear region with increasing F. The DNR occurred approximately at the same F (∼104 V/cm), and the J values in the other two regions proved systematically but differently dependent on the i‐layer thickness. The J value at a low F value in the Ohmic region decreased rapidly below the di value of 10 μm, while for di above 10 μm the J value was constant. In the superlinear region, J for a constant F increased proportionally to di. The origins of these thickness dependences are discussed.
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72.20.Fr Low-field transport and mobility; piezoresistance
72.20.Ht High-field and nonlinear effects
72.80.Ng Disordered solids
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Molecular beam epitaxial growth of a novel strained‐layer superlattice system: CdTe‐ZnTe

G. Monfroy, S. Sivananthan, X. Chu, J. P. Faurie, R. D. Knox, and J. L. Staudenmann

Appl. Phys. Lett. 49, 152 (1986); http://dx.doi.org/10.1063/1.97208 (3 pages) | Cited 33 times

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CdTe‐ZnTe strained‐layer superlattices have been grown for the first time using the molecular beam epitaxy technique. The superlattices have been grown at 285 °C. They have been characterized by electron and x‐ray diffraction. The presence of satellite peaks in the x‐ray spectra shows that the superlattices are of excellent quality despite the large mismatch between CdTe and ZnTe along the growth axis (Δa/a=6.4%). X‐ray oscillation patterns show that the superlattices are three‐dimensional crystals.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.-a Thin film structure and morphology

High photoconductive gain in GexSi1−x/Si strained‐layer superlattice detectors operating at λ=1.3 μm

H. Temkin, J. C. Bean, T. P. Pearsall, N. A. Olsson, and D. V. Lang

Appl. Phys. Lett. 49, 155 (1986); http://dx.doi.org/10.1063/1.97209 (3 pages) | Cited 15 times

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We demonstrate high photoconductive gain in GexSi1−x/Si strained‐layer superlattice detectors grown by molecular beam epitaxy. The gain mechanism is considered to be the preferential hole trapping in the GexSi1−x wells. Ge0.6Si0.4 waveguide devices operating at the wavelength of 1.3 μm show an optical gain as large as 40 at a low bias of 5–7 V and a gain bandwidth product as large as 3.6 GHz. Preliminary bit error experiments show sensitivity sufficient for transmission at distances of over 25 km and data rates of 200 Mb/s.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Resonant tunneling through a double GaAs/AlAs superlattice barrier, single quantum well heterostructure

M. A. Reed, J. W. Lee, and H‐L. Tsai

Appl. Phys. Lett. 49, 158 (1986); http://dx.doi.org/10.1063/1.97210 (3 pages) | Cited 41 times

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Resonant tunneling has been demonstrated through a double barrier, single quantum well heterostructure in which the barriers have been replaced by thin, short period binary superlattices. The superlattice structure does not exhibit the asymmetry around zero bias in the electrical characteristics normally observed in the conventional AlxGa1−xAs barrier structures, suggestive of reduced roughness at the inverted interface by superlattice smoothing. The structure exhibits an anomalously low barrier height and a peak to valley tunnel current ratio of 1.8:1 at 300 K.
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73.40.Gk Tunneling
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Observation of local lattice distortion induced by In doping in GaAs

Y. Fujiwara, Y. Kita, Y. Tonami, T. Nishino, and Y. Hamakawa

Appl. Phys. Lett. 49, 161 (1986); http://dx.doi.org/10.1063/1.97211 (3 pages) | Cited 9 times

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The In concentration dependence of newly observed Cr‐related luminescence lines has been systematically investigated by a low‐temperature photoluminescence (PL) method in In,Cr‐codoped GaAs. As a result, it has been found that the luminescence center of these In,Cr‐related PL lines is a complex of InGa‐CrGa‐VAs. Furthermore, their relative peak positions with respect to the well‐known Cr‐VAs PL line have been analyzed by using uniaxial stress data, the result suggesting that local lattice distortion of about 1% is induced by In doping in GaAs.
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78.40.Fy Semiconductors
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Optical properties of very thin GaInAs(P)/InP quantum wells grown by gas source molecular beam epitaxy

M. B. Panish, H. Temkin, R. A. Hamm, and S. N. G. Chu

Appl. Phys. Lett. 49, 164 (1986); http://dx.doi.org/10.1063/1.97212 (3 pages) | Cited 49 times

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Single quantum wells of GaInAs and GaInAsP isolated by 150‐Å‐thick InP barriers have been grown by gas source molecular beam epitaxy. The quantum wells ranged in thickness from 5 to 30 Å. Photoluminescence and transmission electron microscopy were used to characterize them. Intense luminescence was observed at low temperature even from the thinnest of the wells. The spectral shifts due to the quantum size effect were 450 meV for the quaternary 5‐Å well and 534 meV for the ternary 5‐Å well. The latter constitutes approximately 85% of the total band‐gap discontinuity. The emission linewidths suggest that on a scale larger than the exciton diameter the interface fluctuates less than one monolayer.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.40.Fy Semiconductors
75.20.Ck Nonmetals
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Electron beam induced current and cathodoluminescence study of the recombination activity of stacking faults and hillocks in hydride vapor phase epitaxy InP

G. Attolini, C. Frigeri, C. Pelosi, and G. Salviati

Appl. Phys. Lett. 49, 167 (1986); http://dx.doi.org/10.1063/1.97213 (3 pages) | Cited 2 times

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Cathodoluminescence and electron beam induced current modes in the scanning electron microscope have been employed to study the recombination behavior of stacking faults and surrounding hillocks in undoped InP homoepitaxies grown by hydride vapor phase epitaxy. Stacking faults exhibited nonradiative recombination activity. The largest hillocks with {111} type outer surfaces showed enhanced radiative recombination on two opposite sides and no recombination on the other two, most probably because of the different incorporation of the unintentional dopant. The greater influence that the largest hillocks have, compared with the crystallographic defects, in limiting the electrical but not the optoelectronic performances of the homoepitaxies, is pointed out.
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68.35.Dv Composition, segregation; defects and impurities
78.60.Hk Cathodoluminescence, ionoluminescence
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)

Chemical beam epitaxial growth of extremely high quality InGaAs on InP

W. T. Tsang, A. H. Dayem, T. H. Chiu, J. E. Cunningham, E. F. Schubert, J. A. Ditzenberger, J. Shah, J. L. Zyskind, and N. Tabatabaie

Appl. Phys. Lett. 49, 170 (1986); http://dx.doi.org/10.1063/1.97214 (3 pages) | Cited 20 times

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Full widths at half‐maximum intensity of the (004) Bragg reflecton peak as small as 24 arcs are obtained from InGaAs epilayers 4–6 μm thick. Such linewidth is the narrowest reported thus far for an InGaAs epilayer grown by any vapor phase technique reported in literature. Such extreme compositon uniformity is also supported by results from Auger depth profiles and 2 K photoluminescence measurements. Very intense efficient luminescence peaks due to excitonic transitions with linewidths (FWHM) as narrow as 1.2 meV are obtained. This again represents the narrowest linewidth ever reported for InGaAs grown by any technique. In fact, such a linewidth represents the narrowest linewidth ever measured for any alloy semiconductor. Further, the photoluminescence spectra reveal the donor‐to‐acceptor pair recombination is nearly absent. This indicates that the InGaAs is of very high purity. Hall measurements of 2–5‐μm‐thick epilayers grown directly on InP substrates have mobilities of 10 000–12 000 and 40 000–57 000 cm2/V s at 300 and 77 K with n=5×1014–5×1015 cm−3. These values are among the highest of all the results for InGaAs grown by other techniques.
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78.40.Fy Semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
72.20.My Galvanomagnetic and other magnetotransport effects

Surface photovoltage measurement of light instability of amorphous silicon films

K. A. Epstein, N. T. Tran, F. R. Jeffrey, and A. R. Moore

Appl. Phys. Lett. 49, 173 (1986); http://dx.doi.org/10.1063/1.97215 (3 pages) | Cited 9 times

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The effect of prolonged light exposure on photovoltaic quality of glow discharge amorphous silicon films has been studied by the surface photovoltage technique. Two principal results have been observed. (i) The minority‐carrier diffusion length degrades but stabilizes at 0.25–0.3 μm. (ii) The space‐charge width collapses at open circuit voltage under as little as 0.0001 sun bias illumination. The combination of these two effects suggests that it is gross changes in the built‐in electric fields that most seriously degrade the fill factor in amorphous silicon solar cells, rather than changes in μτ.
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73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
84.60.Jt Photoelectric conversion
72.40.+w Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Analytic Boltzmann equation approach for negative differential mobility in two‐valley semiconductors

Christopher J. Stanton, Harold U. Baranger, and John W. Wilkins

Appl. Phys. Lett. 49, 176 (1986); http://dx.doi.org/10.1063/1.97216 (3 pages) | Cited 3 times

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We present results for the negative differential mobility and the distribution function in GaAs and InP for electric fields less than 40 kV/cm based on the analytic solution of the Boltzmann equation for a model with two valleys and three relaxation times. Using the measured low field mobility, lower valley mass, and valley separation energy Δ while adjusting three upper valley parameters, we obtain good agreement with the experimental velocity‐field curves. The distribution function in the lower valley shows structure at energies ≊Δ due to the intervalley scattering.
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72.20.Fr Low-field transport and mobility; piezoresistance
72.20.Ht High-field and nonlinear effects
72.20.Dp General theory, scattering mechanisms

Heterojunction bipolar transistor using pseudomorphic GaInAs for the base

P. M. Enquist, L. R. Ramberg, F. E. Najjar, W. J. Schaff, and L. F. Eastman

Appl. Phys. Lett. 49, 179 (1986); http://dx.doi.org/10.1063/1.97217 (2 pages) | Cited 7 times

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We report on replacing the GaAs base in the AlGaAs/GaAs heterojunction bipolar transistor with pseudomorphic GaInAs. Base regions consisting of uniform Ga0.95In0.05As and graded Ga1−yInyAs (y=0.0–0.05) are compared to base regions consisting of GaAs. The highest dc common emitter current gain is obtained with the graded Ga1−yInyAs base.
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85.30.Pq Bipolar transistors

Laser induced enhancement in sensitivity of polymeric nuclear track detector CR‐39

L. M. Kukreja, V. B. Joshi, A. M. Bhagwat, U. K. Chatterjee, and D. D. Bhawalkar

Appl. Phys. Lett. 49, 181 (1986); http://dx.doi.org/10.1063/1.97218 (2 pages) | Cited 2 times

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It is found that the polymer CR‐39 treated with a cw CO2 laser at a fluence between 13 and 30 J cm−2 shows enhancement in its track revelation sensitivity up to 1.6 times for the α particles and 1.8 times for the fission fragments from a 252Cf source.
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29.40.Rg Nuclear emulsions
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.65.-b Surface treatments
79.20.Ds Laser-beam impact phenomena
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