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9 Feb 1987

Volume 50, Issue 6, pp. 301-361


Effect of compositionally graded and superlattice buffer layers on the device performance of graded barrier quantum well heterostructure laser diodes

M. E. Givens, L. J. Mawst, C. A. Zmudzinski, M. A. Emanuel, and J. J. Coleman

Appl. Phys. Lett. 50, 301 (1987); http://dx.doi.org/10.1063/1.98231 (3 pages) | Cited 6 times

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The device performance of graded barrier quantum well laser diodes with various buffer layer structures grown by metalorganic chemical vapor deposition has been studied. Devices having four structures (a GaAs buffer layer only, a compositionally graded buffer layer, a superlattice buffer layer, or both a graded and a superlattice buffer layer) have been characterized. In contrast with similar studies involving laser devices grown by molecular beam epitaxy, little variation in device performance is observed. These data indicate that the quality of AlGaAs‐GaAs heterostructures for optical devices may be dependent on the details of the method used for the epitaxial growth of the layers.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
42.60.By Design of specific laser systems

Temporal evolutions of frequency resolved radiations from a Raman regime free‐electron laser

Nobuhisa Ohigashi, Masanobu Morita, Kunioki Mima, Syuji Miyamoto, Kazuo Imasaki, Shinichiro Kuruma, Sadao Nakai, Chiyoe Yamanaka, Toshihiro Taguchi, and Akira Murai

Appl. Phys. Lett. 50, 304 (1987); http://dx.doi.org/10.1063/1.98232 (3 pages) | Cited 3 times

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In pulse power driven free‐electron laser experiments for a diode voltage 300–600 kV, a maximum electron beam current 730 A, with a 110‐ns width of beam voltage pulse and a helical wiggler with a pitch of 2 cm, the temporal evolution of radiation spectra is observed. The frequency variations are explained theoretically by using instantaneous values of beam voltages and currents. In the calculation we take account of the variation in the beam cross section of the beam voltage drop and the wiggler field. The spatial growth rate of the radiation power was also measured. The observed growth rate is 1 dB/cm and the saturation level is 250 kW with the spector peak at 58 GHz.
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41.60.Cr Free-electron lasers
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
42.65.Dr Stimulated Raman scattering; CARS
42.65.Es Stimulated Brillouin and Rayleigh scattering

Spectral dependence of propagation loss in InP/InGaAsP antiresonant reflecting optical waveguides grown by chemical beam epitaxy

T. L. Koch, W. T. Tsang, and P. J. Corvini

Appl. Phys. Lett. 50, 307 (1987); http://dx.doi.org/10.1063/1.98233 (3 pages) | Cited 9 times

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We present direct measurement of low propagation loss in InP‐core antiresonant reflecting optical waveguides (ARROW’s) at wavelengths that are strongly absorbed in the directly adjacent InGaAsP reflector layers. With 1.54‐μm luminescence peak InGaAsP reflector layers, losses range from a low value of ∼0.9 dB/cm at 1.67 μm to ∼6.5 dB/cm at a wavelength of 1.515 μm for which the reflector layer losses approach 104 dB/cm. This proves the suitability of the ARROW geometry for providing large mode, low propagation loss guides for wavelengths that may either be generated, experience gain, or absorption within the reflector layers.
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42.79.Gn Optical waveguides and couplers
42.82.-m Integrated optics
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
42.79.Sz Optical communication systems, multiplexers, and demultiplexers

Measurement of radiative, Auger, and nonradiative currents in 1.3‐μm InGaAsP buried heterostructure lasers

Robert Olshansky, Joanne LaCourse, Terrance Chow, and William Powazinik

Appl. Phys. Lett. 50, 310 (1987); http://dx.doi.org/10.1063/1.98234 (3 pages) | Cited 29 times

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Frequency response measurements are used to determine the carrier lifetime of 1.3‐μm InGaAsP buried heterostructure lasers between 1 mA and threshold. The data confirm previous results on the radiative and Auger recombination coefficients and reveal the presence of a nonradiative current which dominates at low currents and contributes 4 mA at threshold.
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42.55.Px Semiconductor lasers; laser diodes
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Multikilowatt compact axial flow CO2 laser

J. E. Harry and D. R. Evans

Appl. Phys. Lett. 50, 313 (1987); http://dx.doi.org/10.1063/1.98235 (3 pages) | Cited 7 times

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A high power, compact axial flow CO2 laser is described with a power output of 3.5 kW and a discharge length of 0.6 m using an unfolded cavity. The high power per unit length is achieved by the use of multiple electrodes with gas injection through porous anodes. Discharge currents of more than 2 A and cavity diameters up to 150 mm have been used with 12 anodes without the glow to arc transition occurring. An electrical to optical conversion efficiency of 23% has been achieved. The results indicate the effect of the current density and degree of turbulence in the transition regions of the discharges adjacent to the anodes in offsetting the glow to arc transition.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Dynamics of a rf sheath in the range between the ionic and the electronic plasma frequencies

A. M. Pointu

Appl. Phys. Lett. 50, 316 (1987); http://dx.doi.org/10.1063/1.98236 (2 pages) | Cited 21 times

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The dynamics of an ionic sheath submitted to a periodic field with a frequency between the ionic and the electronic plasma frequencies is analyzed under one‐dimensional, noncollisional, and thick sheath assumptions. Accordingly the displacement current is calculated.
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52.40.Hf Plasma-material interactions; boundary layer effects
52.80.Pi High-frequency and RF discharges

Laser induced fluorescence detection of CF and CF2 radicals in a CF4/O2 plasma

J. P. Booth, G. Hancock, and N. D. Perry

Appl. Phys. Lett. 50, 318 (1987); http://dx.doi.org/10.1063/1.98214 (2 pages) | Cited 31 times

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Laser induced fluorescence has been used to detect ground‐state CF and CF2 radicals in a CF4/O2 plasma etching reactor. Measurements are reported of the spatial variation of CF2 concentrations, of the CF radical rotational state distributions, and of the variation of both species with O2 content of the plasma.
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33.50.Dq Fluorescence and phosphorescence spectra
81.65.-b Surface treatments
52.75.-d Plasma devices
52.25.-b Plasma properties

Structure of ultrathin silicon dioxide films

Ian W. Boyd and John I. B. Wilson

Appl. Phys. Lett. 50, 320 (1987); http://dx.doi.org/10.1063/1.98187 (3 pages) | Cited 23 times

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Differential infrared spectroscopy has been used to study the silicon‐oxygen stretching band of thin silicon dioxide films thermally grown on single‐crystal silicon. We consistently observe an asymmetry in the spectra of films thicker than about 100 Å, of about 9 cm−1. The peak position, width, and degree of asymmetry are also found to be sensitively dependent upon film thickness below 100–150 Å, while above this level these features are only very weakly dependent upon film thickness, indicating the presence of a thin layer of different structural or bonding properties. Our interpretation suggests that the infrared spectra of layers up to 100 Å thick are significantly affected by strain originating at the silicon‐oxide interface, in agreement with recent observations.
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68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.65.-b Surface treatments
78.30.Hv Other nonmetallic inorganics

Raman scattering from rapid thermally annealed tungsten silicide

Sandeep Kumar, Samhita Dasgupta, Howard E. Jackson, and Joseph T. Boyd

Appl. Phys. Lett. 50, 323 (1987); http://dx.doi.org/10.1063/1.98188 (3 pages) | Cited 2 times

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Raman scattering as a technique for studying the formation of tungsten silicide is presented. The tungsten silicide films have been formed by rapid thermal annealing of thin tungsten films sputter deposited on silicon substrates. The Raman data are interpreted by using data from resistivity measurements, Auger and Rutherford backscattering measurements, and scanning electron microscopy.
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81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
78.30.Er Solid metals and alloys
73.61.At Metal and metallic alloys
78.66.Bz Metals and metallic alloys

Energy‐band discontinuities in a heterojunction of amorphous hydrogenated Si and crystalline Si measured by internal photoemission

Hidenori Mimura and Yoshinori Hatanaka

Appl. Phys. Lett. 50, 326 (1987); http://dx.doi.org/10.1063/1.98189 (3 pages) | Cited 34 times

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Energy‐band discontinuities were measured for hydrogenated amorphous silicon and crystalline silicon heterojunctions by internal photoemission. The measurement was performed both for the conduction‐band side and for the valence‐band side, and the conduction‐band discontinuity and the valence‐band discontinuity were estimated to be 0.09 and 0.71 eV, respectively. This result indicates that the band discontinuity mainly exists at the valence‐band side.
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73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.65.-b Surface treatments
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.20.At Surface states, band structure, electron density of states

Programmed magnetic field applied liquid encapsulated Czochralski crystal growth

Shoichi Ozawa, Tadashi Kimura, Junji Kobayashi, and Tsuguo Fukuda

Appl. Phys. Lett. 50, 329 (1987); http://dx.doi.org/10.1063/1.98190 (3 pages) | Cited 4 times

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We have developed a programmed magnetic field applied liquid encapsulated Czochralski crystal growth technique which produces a homogeneous impurity distribution along the growth axis of the crystal. In this technique the magnetic field strength is controlled in a programmed manner during growth. The results of growing iron‐doped InP crystal with this technique are presented.
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81.10.Fq Growth from melts; zone melting and refining
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
61.72.U- Doping and impurity implantation
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors

Observation of millimeter‐wave oscillations from resonant tunneling diodes and some theoretical considerations of ultimate frequency limits

T. C. L. G. Sollner, E. R. Brown, W. D. Goodhue, and H. Q. Le

Appl. Phys. Lett. 50, 332 (1987); http://dx.doi.org/10.1063/1.98191 (3 pages) | Cited 56 times

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Recent observations of oscillation frequencies up to 56 GHz in resonant tunneling structures are discussed in relation to calculations by several authors of the ultimate frequency limits of these devices. We find that calculations relying on the Wentzel–Kramers–Brillouin (WKB) approximation give limits well below the observed oscillation frequencies. Two other techniques for calculating the upper frequency limit were found to give more reasonable results. In one method we use the solution of the time‐dependent Schrödinger equation obtained by Kundrotas and Dargys [Phys. Status Solidi B 134, 267 (1986)], while in the other we use the energy width of the transmission function for electrons through the double‐barrier structure. This last technique is believed to be the most accurate since it is based on general results for the lifetime of any resonant state. It gives frequency limits on the order of 1 THz for two recently fabricated structures. It appears that the primary limitation of the oscillation frequency for double‐barrier resonant tunneling diodes will be imposed by intrinsic device circuit parameters and by the transit time of the depletion layer rather than by time delays encountered in the double‐barrier region.
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85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
73.40.Gk Tunneling
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Influence of microstructure on the photoconductivity of glow discharge deposited amorphous SiC:H and amorphous SiGe:H alloys

A. H. Mahan, P. Raboisson, and R. Tsu

Appl. Phys. Lett. 50, 335 (1987); http://dx.doi.org/10.1063/1.98192 (3 pages) | Cited 52 times

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We introduce a parameter obtained from infrared measurements as a means of quantifying the amount of amorphous silicon microstructure and its degree of passivation by hydrogen. Using this parameter, the photoconductivities of amorphous silicon (a‐Si:H), amorphous silicon carbon (a‐SiC:H), and amorphous silicon germanium (a‐SiGe:H) fall on the same curve. We discuss the relevance of these results with regard to material quality.
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68.55.-a Thin film structure and morphology
81.65.-b Surface treatments
73.50.Pz Photoconduction and photovoltaic effects
84.60.Jt Photoelectric conversion

Ledistor—a three‐terminal double heterostructure optoelectronic switch

G. W. Taylor, R. S. Mand, J. G. Simmons, and A. Y. Cho

Appl. Phys. Lett. 50, 338 (1987); http://dx.doi.org/10.1063/1.98193 (3 pages) | Cited 12 times

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A three‐terminal double heterostructure optoelectronic switching (DOES) device is demonstrated. By making ohmic contact to the active region of the DOES device the switching characteristic may be controlled up to the punchthrough limit. The device emits light in the on state only and various combinations of voltage and optical input power can be used to switch the device.
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85.60.-q Optoelectronic devices
84.32.Dd Connectors, relays, and switches
85.30.De Semiconductor-device characterization, design, and modeling
42.55.Px Semiconductor lasers; laser diodes

Study of interface states in the metal‐semiconductor junction using deep level transient spectroscopy

Han Zhang, Yoshinobu Aoyagi, Sohachi Iwai, and Susumu Namba

Appl. Phys. Lett. 50, 341 (1987); http://dx.doi.org/10.1063/1.98194 (3 pages) | Cited 19 times

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A new technique is reported for determining the interface states in the metal‐semiconductor junction by deep level transient spectroscopy. The continuous interface state distribution in the Al‐GaAs junction has been studied for the energy range from 0.19 to 0.57 eV below conduction band by the technique and it is found to be of the order of 4.3×1010–7.9×1010 eV−1 cm−2. The results have shown that the technique is very effective and credible.
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73.20.At Surface states, band structure, electron density of states
73.40.Ns Metal-nonmetal contacts
73.30.+y Surface double layers, Schottky barriers, and work functions
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Observation of resonant tunneling through GaAs quantum well states confined by AlAs X‐point barriers

A. R. Bonnefoi, T. C. McGill, R. D. Burnham, and G. B. Anderson

Appl. Phys. Lett. 50, 344 (1987); http://dx.doi.org/10.1063/1.98195 (3 pages) | Cited 40 times

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Experimental evidence of resonant tunneling via quasistationary states confined by AlAs X‐point potential energy barriers is reported in GaAs/AlAs double barrier heterostructures grown in the [100] direction. The quantum well energy levels giving rise to the negative differential resistances observed in the current‐voltage characteristics are identified by calculating the energy‐band diagrams of the structures. These resonant energy levels correspond to states confined in the GaAs well not only by the AlAs Γ‐point potential energy barriers but also by the AlAs X‐point barriers. The quasibound X states are associated with the large longitudinal effective mass in AlAs corresponding to the direction perpendicular to the heterojunction interfaces.
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73.40.Gk Tunneling
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Ey III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Molecular beam epitaxy of GaAs/AlGaAs superlattice heterostructures on nonplanar substrates

E. Kapon, M. C. Tamargo, and D. M. Hwang

Appl. Phys. Lett. 50, 347 (1987); http://dx.doi.org/10.1063/1.98196 (3 pages) | Cited 110 times

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GaAs/AlGaAs superlattice heterostructures with layer thicknesses ≲100 Å were grown by molecular beam epitaxy on nonplanar GaAs substrates. The resulting superlattices exhibit different periods, depending on the crystal plane on which they grow. Period variation of more than 50%, from 180 to 80 Å, was obtained for adjacent superlattice sections. The transition between regions of different periodicity was mostly smooth and occurred within lateral dimensions ≲100 Å. Our results suggest that molecular beam epitaxy of superlattice heterostructures on patterned substrates provides a method for obtaining controllable lateral variations in physical properties which depend on the superlattice period. In particular, by growing quantum well heterostructures on nonplanar substrates, it might be possible to utilize the strong dependence of the carrier confinement energy on the well thickness in order to achieve lateral carrier confinement.
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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

Subpicosecond optoelectronic study of resistive and superconductive transmission lines

W. J. Gallagher, C.‐C. Chi, I. N. Duling, D. Grischkowsky, N. J. Halas, M. B. Ketchen, and A. W. Kleinsasser

Appl. Phys. Lett. 50, 350 (1987); http://dx.doi.org/10.1063/1.98197 (3 pages) | Cited 19 times

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We have studed the propagation of subpicosecond electrical pulses on coplanar resistive and superconductive Nb transmission lines. Pulses with 0.9 ps full width at half maximum were generated and detected by shorting fast photoconductive switches with 80 fs laser pulses. Dramatic improvements in propagation characteristics were achieved when the Nb was superconductive. We observed the strong dispersion and attenuation predicted to occur for frequency components near the superconducting enery gap frequency.
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84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
85.25.-j Superconducting devices
74.78.-w Superconducting films and low-dimensional structures
74.25.N- Response to electromagnetic fields

Microstructural investigation of Nd‐Fe‐B with the scanning tunneling microscope

B. W. Corb, M. Ringger, H.‐J. Güntherodt, and F. E. Pinkerton

Appl. Phys. Lett. 50, 353 (1987); http://dx.doi.org/10.1063/1.98267 (3 pages) | Cited 6 times

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The first investigation of rapidly quenched Nd‐Fe‐B permanent magnet material with the scanning tunneling microscope revealed that Nd‐Fe‐B has a faceted spheroidal grain structure with a grain size of 200 Å. Barrier height measurements indicate that the grains are often either of slightly different chemical compositions or more likely of different crystallographic orientation.
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61.72.Mm Grain and twin boundaries
61.66.Dk Alloys
07.55.Db Generation of magnetic fields; magnets
85.70.-w Magnetic devices

Direct overwrite in amorphous rare‐earth transition‐metal alloys

P. Hansen

Appl. Phys. Lett. 50, 356 (1987); http://dx.doi.org/10.1063/1.98198 (3 pages) | Cited 8 times

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The thermomagnetic writing and erasure process has been investigated, paying special attention to the case of zero applied magnetic field. Concerning bubblelike domains, writing can easily be performed by the demagnetizing field while erasure requires an external magnetic field larger than the collapse field. However, in alloys exhibiting a compensation temperature above ambient temperature erasure can be achieved in the absence of an external field via the creation and annihilation of a ring domain which opens the capability of direct overwrite.
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75.50.Kj Amorphous and quasicrystalline magnetic materials
75.70.Kw Domain structure (including magnetic bubbles and vortices)
72.15.Jf Thermoelectric and thermomagnetic effects
85.70.Sq Magnetooptical devices

Characterization of the pulsed laser evaporation process: Selenium thin‐film formation

S. G. Hansen and T. E. Robitaille

Appl. Phys. Lett. 50, 359 (1987); http://dx.doi.org/10.1063/1.98199 (3 pages) | Cited 23 times

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Selenium (Se) films were prepared by pulsed laser evaporation of the elemental powder in vacuum. Film growth rates as a function of average laser power (0.1–5 W/cm2) and wavelength (266–1064 nm) were measured. The angular distribution of evaporated material was found to be unusually narrow for wavelengths shorter than the Se absorption edge (∼600 nm). The photon efficiency for evaporation ranged from 0.4 to 0.1 atoms/photon for 266 to 1064 nm light, respectively.
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81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
79.20.Ds Laser-beam impact phenomena
68.55.-a Thin film structure and morphology
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