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10 Jan 1994

Volume 64, Issue 2, pp. 131-258

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Transparent chemical vapor deposited β‐SiC

J. S. Goela, L. E. Burns, and R. L. Taylor

Appl. Phys. Lett. 64, 131 (1994); http://dx.doi.org/10.1063/1.111541 (3 pages) | Cited 7 times

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Transparent β‐SiC has been fabricated by the pyrolysis of methyltrichlorosilane in a hot wall chemical vapor deposition reactor. Characterization of material indicates that transparent SiC is a theoretically dense, highly pure (99.9996%), highly oriented 〈111〉, β‐phase (cubic) material possessing high optical transmission in the wavelength region 0.5–6 μm, a high value of hardness, electrical resistivity and thermal conductivity, and a low value of thermal expansion coefficient. These properties make it a good candidate material for use as domes and windows in severe environments such as high speed missiles, laser, combustion and space systems.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
42.70.Km Infrared transmitting materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.30.Hv Other nonmetallic inorganics

Wavelength‐selective detector based on a quantum well in a standing wave

L. Carraresi, E. A. De Souza, D. A. B. Miller, W. Y. Jan, and J. E. Cunningham

Appl. Phys. Lett. 64, 134 (1994); http://dx.doi.org/10.1063/1.111542 (3 pages) | Cited 9 times

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We present an example of a new class of optoelectronic devices realized by placing thin absorbers in a standing wave. Using quantum wells as absorbers and measuring the photocurrent from each of them separately it is possible to realize devices which accomplish complex tasks like separately detecting more than one wavelength at the same time or measuring the wavelength of a quasimonochromatic beam. In this letter we demonstrate a wavelength‐selective detector based on a single quantum well. It detects at 850 nm with a bandwidth <10 nm, while rejecting at the shorter wavelength of 835 nm by a factor of 120.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
78.66.Fd III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
72.40.+w Photoconduction and photovoltaic effects

Generation of tunable narrow‐band THz radiation from large aperture photoconducting antennas

A. S. Weling, B. B. Hu, N. M. Froberg, and D. H. Auston

Appl. Phys. Lett. 64, 137 (1994); http://dx.doi.org/10.1063/1.111543 (3 pages) | Cited 42 times

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We report a novel technique for the generation of tunable narrow‐band submillimeter wave electromagnetic radiation in free space. This is accomplished by mixing two linearly chirped optical pulses with a variable time delay on a biased large aperture GaAs photoconducting antenna. The center frequency of the THz radiation varies linearly with the delay between the two chirped pulses from dc to ∼1 THz.
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85.60.-q Optoelectronic devices
84.40.-x Radiowave and microwave (including millimeter wave) technology
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Polarization and wavelength dependence of metal‐semiconductor‐metal photodetector response

J. J. Kuta, H. M. van Driel, D. Landheer, and J. A. Adams

Appl. Phys. Lett. 64, 140 (1994); http://dx.doi.org/10.1063/1.111544 (3 pages) | Cited 12 times

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Photocurrent and transmission studies for 543<λ<1523 nm of metal‐semiconductor‐metal (MSM) photodetectors on semi‐insulating GaAs substrates demonstrate a polarization and wavelength dependence of the coupling of light into the metal electrodes. Devices with electrode periods of 400 and 800 nm were investigated and differences as large as 85% in efficiency between orthogonal polarizations were measured for the 400 nm devices. Modeling of the energy transmission through lamellar periodic structures using a Greens function formalism and incorporating dispersion of the substrate dielectric constant produces semiquantitative agreement with the measurements. Suggestions for future MSM photodetector design are discussed.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
72.40.+w Photoconduction and photovoltaic effects
73.40.Sx Metal-semiconductor-metal structures

Carrier temperature and spectral holeburning dynamics in InGaAsP quantum well laser amplifiers

M. Willatzen, J. Mark, J. Mørk, and C. P. Seltzer

Appl. Phys. Lett. 64, 143 (1994); http://dx.doi.org/10.1063/1.111545 (3 pages) | Cited 13 times

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An experimental and theoretical study of ultrafast gain dynamics in InGaAsP multiple quantum well laser amplifiers is presented. A transition from pump‐induced heating of the carriers to pump‐induced cooling is observed by change of the pump‐probe wavelength. The experimental results are in good agreement with a theoretical model including the effects of carrier temperature dynamics, spectral holeburning, and two‐photon absorption.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
78.47.-p Spectroscopy of solid state dynamics

Accelerated aging for AlGaInP visible laser diodes

Kenji Endo, Kennichi Kobayashi, Hiroaki Fujii, and Yoshiyasu Ueno

Appl. Phys. Lett. 64, 146 (1994); http://dx.doi.org/10.1063/1.111546 (3 pages) | Cited 10 times

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Accelerated aging tests were carried out under constant current conditions at an ambient temperature range of 100–150 °C for 670 nm band AlGaInP visible laser diodes. A degradation rate activation energy of 0.8 eV and an extrapolated lifetime of 106 h at 50 °C has been obtained. It is reported for the first time that lasing wavelength shifts of up to 20 nm to shorter wavelengths accompanied the threshold current increase. This is attributed to disordering of the natural superlattice in the GaInP active layer.    
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Soliton versus nonsoliton operation of fiber ring lasers

K. Tamura, L. E. Nelson, H. A Haus, and E. P. Ippen

Appl. Phys. Lett. 64, 149 (1994); http://dx.doi.org/10.1063/1.111547 (3 pages) | Cited 52 times

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To date most passively mode‐locked erbium‐doped fiber laser systems have employed solitons for short pulse generation, and ultrashort high energy pulses have been difficult to achieve. We show that by reducing the system nonlinearity via pulse stretching and employing net positive dispersion cavities, pulses of sub‐100‐fs duration and ≳100 pJ energy are readily generated. Data are presented for varying net dispersion in a fiber ring.
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42.55.Wd Fiber lasers
42.60.Fc Modulation, tuning, and mode locking
42.81.Dp Propagation, scattering, and losses; solitons

High‐power diode‐laser‐pumped InAsSb/GaSb and GaInAsSb/GaSb lasers emitting from 3 to 4 μm

H. Q. Le, G. W. Turner, S. J. Eglash, H. K. Choi, and D. A. Coppeta

Appl. Phys. Lett. 64, 152 (1994); http://dx.doi.org/10.1063/1.111548 (3 pages) | Cited 28 times

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Diode‐array‐pumped GaInAsSb/GaSb and InAsSb/GaSb double heterostructure lasers operated at 85 K yielded 95 mW average and 1.5 W peak power per facet at 3 μm, and 50 mW average and 0.8 W peak power facet at 4 μm. The highest operational temperature was 210 K for the 3‐μm quaternary and 150 K for the 4‐μm ternary.
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42.55.Px Semiconductor lasers; laser diodes
42.60.-v Laser optical systems: design and operation

Blue light generation using bulk single crystals of niobium‐doped KTiOPO4

L. T. Cheng, L. K. Cheng, R. L. Harlow, and J. D. Bierlein

Appl. Phys. Lett. 64, 155 (1994); http://dx.doi.org/10.1063/1.111549 (3 pages) | Cited 27 times

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We report here new solid‐solution KTiOPO4 (KTP) isomorphs, namely K1−xNbxTi1−xOPO4 and K1−xTaxTi1−xOPO4, suitable for the second‐harmonic generation (SHG) of blue light. Aliovalent substitution of the Ti4+‐K+ pair in KTP with Nb5+ or Ta5+ increases substantially the optical birefringence (nz−ny,x) of KTP, and blueshifts the SHG cutoff wavelengths for propagation along the x and y axes. A birefringence increase of ∼70%, and a SHG cutoff wavelength as short as 892 nm have been experimentally observed in crystals of K1−xNbxTi1−xOPO4. Detailed single‐crystal x‐ray structure determination reveals that the Nb substitution is ordered, with Nb strongly favoring the cis‐Ti(1) sites. We discuss possible correlation between this preferential substitution and the observed compositional dependence of nonlinear susceptibilities d24, and d15. Optimal solid‐solution compositions for the noncritically phase‐matched frequency doubling of the 1.064 and 0.946 μm lines of Nd:YAG lasers are presented, and potential applications for these new materials are outlined.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Highly efficient TE/TM mode switching of GaAsP/AlGaAs strained quantum‐well laser diodes

Hidenao Tanaka, Jun‐ichi Shimada, and Yoshio Suzuki

Appl. Phys. Lett. 64, 158 (1994); http://dx.doi.org/10.1063/1.111956 (3 pages) | Cited 9 times

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TE/TM mode switching is demonstrated in GaAsP/AlGaAs tensilely strained quantum‐well laser diodes with two electrodes. The laser diode oscillated in the TM mode when current was injected into both electrodes, and oscillated in the TE mode when current was injected only into the longer electrode. The mode was switched by controlling the injection current of the two electrodes. The modulation efficiency of the TM‐mode output selected by a polarizer was very high (15 W/A) in this mode switching.
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42.55.Px Semiconductor lasers; laser diodes
42.55.Rz Doped-insulator lasers and other solid state lasers

Pulsed excimer laser deposition of potassium titanyl phosphate films

Fulin Xiong, R. P. H. Chang, M. E. Hagerman, V. L. Kozhevnikov, K. R. Poeppelmeier, Haitain Zhou, G. K. Wong, J. B. Ketterson, and C. W. White

Appl. Phys. Lett. 64, 161 (1994); http://dx.doi.org/10.1063/1.111551 (3 pages) | Cited 9 times

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Nonlinear optical thin films of potassium titanyl phosphate (KTP) have been successfully fabricated by pulsed excimer laser deposition on substrates of sapphire and Si. The films deposited on sapphire substrates in the temperature ranges of 450–550 °C show good crystallinity with preferential (100) and (011) orientations; on silicon, the films are polycrystalline. The stoichiometry of the films has been found to be Ti rich (about 20% higher). The effective refractive index of the films has been evaluated by spectroscopic ellipsometry with values between 1.75 and 2.0 in the spectral region 0.3–0.9 μm, consistent with the bulk value. The deposited films show a promising nonlinear optical response with high second‐harmonic generation efficiency, comparable to that of single‐crystal KTP.
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81.15.Fg Pulsed laser ablation deposition
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.66.Nk Insulators
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Reflection of surface acoustic waves on domain walls in a LiNbO3 crystal

D. V. Roshchupkin, M. Brunel, R. Tucoulou, E. Bigler, and N. G. Sorokin

Appl. Phys. Lett. 64, 164 (1994); http://dx.doi.org/10.1063/1.111552 (2 pages) | Cited 7 times

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This letter reports on a scanning electron microscopy study of reflection of surface acoustic waves on the domain walls in a LiNbO3 crystal. The regular domain structure with ∼5‐mm period was formed in a LiNbO3 crystal by the method of aftergrowth thermoelectrical treatment. It is shown that the regular domain structure reflects surface acoustic waves on the domain walls in a ferroelectric LiNbO3 crystal.
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77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
77.80.Dj Domain structure; hysteresis
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)

Preparation of aluminum nitride thin films by reactive sputtering and their applications to GHz‐band surface acoustic wave devices

Hiroshi Okano, Naoki Tanaka, Yusuke Takahashi, Toshiharu Tanaka, Kenichi Shibata, and Shoichi Nakano

Appl. Phys. Lett. 64, 166 (1994); http://dx.doi.org/10.1063/1.111553 (3 pages) | Cited 38 times

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Single crystal aluminum nitride (AlN) thin films were prepared by a low‐temperature reactive sputtering on basal plane sapphire [(001)Al2O3] at a substrate temperature of less than 315 °C. Surface acoustic wave (SAW) characteristics with an interdigital transducer /(001)AlN/(001)Al2O3 structure were investigated. The phase velocity and temperature coefficient of delay time are 5750–5765 m/s and 55–63 ppm/°C at KH=1.2–1.6, respectively. Resonator‐type 1‐GHz‐band SAW filters with its structure were fabricated. The insertion loss and suppression were 23 dB and more than 20 dB, respectively.
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68.55.-a Thin film structure and morphology
42.79.Jq Acousto-optical devices
77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics

Deflection of ions due to electric field perturbation in electron cyclotron resonance discharges

M. Ardehali

Appl. Phys. Lett. 64, 169 (1994); http://dx.doi.org/10.1063/1.111554 (3 pages) | Cited 4 times

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Monte Carlo methods have been used to simulate the transport of ions across the sheath of electron cyclotron resonance discharges. It is found that the local electrical field near the wafer surface is distorted by the geometric shape of the trench, and the nature of this distortion is such that the otherwise normally incident ions are deflected toward the trench sidewalls. The simulation results indicate that the degree of ion deflection due to surface topography scales with the trench depth relative to the sheath thickness and not with the aspect ratio.
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81.65.-b Surface treatments
52.65.-y Plasma simulation
52.50.Gj Plasma heating by particle beams
52.80.-s Electric discharges

Analysis of strain and mosaicity in a short‐period Si9Ge6 superlattice by x‐ray diffraction

E. Koppensteiner, P. Hamberger, G. Bauer, V. Holy, and E. Kasper

Appl. Phys. Lett. 64, 172 (1994); http://dx.doi.org/10.1063/1.111555 (3 pages) | Cited 18 times

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Triple axis x‐ray diffractometry was employed for the structural characterization of a 100 period Si9Ge6 superlattice grown by molecular beam epitaxy on a thick step‐graded SiGe alloy buffer. From the distribution of diffusely scattered intensity around reciprocal lattice points the correlation function of the deformation field due to structural defects has been calculated using kinematical theory of x‐ray diffraction. From the extension of the correlation function it turns out that on the average the entire superlattice (0.2 μm thick) scatters coherently along growth direction, whereas laterally the coherently scattering regions are extended only over about 40 nm.
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68.55.-a Thin film structure and morphology
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
61.05.C- X-ray diffraction and scattering

Reduction of secondary defects in BF2 implanted Si(100) by ion beam defect engineering

Qing‐tai Zhao, Zhong‐lie Wang, Tian‐bing Xu, Pei‐ran Zhu, and Jun‐si Zhou

Appl. Phys. Lett. 64, 175 (1994); http://dx.doi.org/10.1063/1.111522 (3 pages) | Cited 3 times

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Reduction of secondary defects in 50 keV, 2×1015 BF2/cm2 implanted Si(100) has been studied by Rutherford backscattering and channeling technique. Secondary defects with high densities have been found in BF2 implanted Si(100) after thermal annealing and rapid thermal annealing. However, a noticeable reduction of secondary defects in BF2 damaged region was observed when a buried amorphous layer was formed by an additional irradiation of 1.0 MeV Si+ ions prior to annealing (i.e., ion beam defect engineering process).
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61.80.Jh Ion radiation effects
61.72.uf Ge and Si
61.72.Cc Kinetics of defect formation and annealing

Ultrasonic force microscopy for nanometer resolution subsurface imaging

Kazushi Yamanaka, Hisato Ogiso, and Oleg Kolosov

Appl. Phys. Lett. 64, 178 (1994); http://dx.doi.org/10.1063/1.111524 (3 pages) | Cited 113 times

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We present a novel method for nanometer resolution subsurface imaging. When a sample of atomic force microscope (AFM) is vertically vibrated at ultrasonic frequencies much higher than the cantilever resonance, the tip cannot vibrate but it is cyclically indented into the sample. By modulating the amplitude of ultrasonic vibration, subsurface features are imaged from the cantilever deflection vibration at the modulation frequency. By adding low‐frequency lateral vibration to the ultrasonic vibration, subsurface features with different shear rigidity are imaged from the torsional vibration of cantilever. Thus controlling the direction of vibration forces, we can discriminate subsurface features of different elastic properties.
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68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
43.35.Yb Ultrasonic instrumentation and measurement techniques

Large scale synthesis of single‐shell carbon nanotubes

X. Lin, X. K. Wang, V. P. Dravid, R. P. H. Chang, and J. B. Ketterson

Appl. Phys. Lett. 64, 181 (1994); http://dx.doi.org/10.1063/1.111525 (3 pages) | Cited 31 times

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We report on a novel technique for synthesizing large quantities of single‐shell carbon nanotubes in a dc arc with a composite anode of graphite and copper. Based on systematic studies involving a varying diameter and distribution of copper rods inside the graphite anode, we have correlated the presence of copper to the formation of monolayer buckytubes. We speculate that copper atoms in the discharge disrupt the orderly formation of multilayer buckytubes observed in earlier experiments.
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61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Laser polymer ablation threshold lowered by nanometer hot spots

Xiaoning Wen, David E. Hare, and Dana D. Dlott

Appl. Phys. Lett. 64, 184 (1994); http://dx.doi.org/10.1063/1.111526 (3 pages) | Cited 20 times

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The effects of nanometer‐sized hot spots on laser polymer ablation are studied. Two polymer thin films are synthesized, containing sensitizers which absorb intense 1.064 μm optical pulses. One film contains a molecular dye sensitizer. The other contains graphic nanoparticle sensitizers (≤220 nm diam). When longer duration pulses (150 ns) which do not produce hot spots are used, both films have the same ablation threshold. When shorter (23 ps) pulses are used, the ablation threshold for graphite films is a factor of 3 less than in dye films, attributed to enhanced polymer thermal decomposition in the vicinity of the larger graphite hot spot.
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81.65.-b Surface treatments
78.66.Qn Polymers; organic compounds
82.50.Bc Processes caused by infrared radiation
82.50.Hp Processes caused by visible and UV light
79.20.Ds Laser-beam impact phenomena

Photocurrent multiplication in organic pigment films

Masahiro Hiramoto, Takashi Imahigashi, and Masaaki Yokoyama

Appl. Phys. Lett. 64, 187 (1994); http://dx.doi.org/10.1063/1.111527 (3 pages) | Cited 38 times

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Large photocurrent multiplication reaching 10 000 times has been observed in a perylene pigment film sandwiched between Au electrodes. The phenomenon occurs at the interface between the perylene film and a negatively biased Au electrode and is found to be associated with electron injection from the Au electrode to the perylene film through the depletion layer formed in the pigment film under a high electric field, which is built up by the photoaccumulated space charges of trapped holes near the interface.
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72.80.Le Polymers; organic compounds (including organic semiconductors)
73.50.Fq High-field and nonlinear effects
73.50.Pz Photoconduction and photovoltaic effects
73.40.Sx Metal-semiconductor-metal structures

Reflection high‐energy electron diffraction intensity oscillations during the growth by molecular beam epitaxy of GaAs (111)A

M. R. Fahy, K. Sato, and B. A. Joyce

Appl. Phys. Lett. 64, 190 (1994); http://dx.doi.org/10.1063/1.111528 (3 pages) | Cited 11 times

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We have made a study of reflection high‐energy electron diffraction intensity oscillations during the growth of GaAs on singular GaAs (111)A substrates by molecular beam epitaxy. The behavior is quite different from growth of GaAs on (001) orientated substrates in that the oscillation period is growth temperature and As4:Ga flux ratio dependent. We speculate that this is due to the (110)‐like configuration of the (111)A 2×2 reconstructed surface, which requires direct interaction of a Ga and an As atom for growth to occur.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)

Thickness dependence of the electrical characteristics of chemical vapor deposited diamond films

M. A. Plano, S. Zhao, C. F. Gardinier, M. I. Landstrass, D. R. Kania, H. Kagan, K. K. Gan, R. Kass, L. S. Pan, S. Han, S. Schnetzer, and R. Stone

Appl. Phys. Lett. 64, 193 (1994); http://dx.doi.org/10.1063/1.111501 (3 pages) | Cited 30 times

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The electrical characteristics of chemically vapor deposited (CVD) diamond films were measured as a function of film thickness. The samples studied were polycrystalline with the average grain size increasing from approximately 1 μm on the substrate side to approximately 30 μm on the growth surface for the thickest sample. Using time‐resolved transient photoconductivity and charged‐particle induced conductivity, the collection distance (d) that a free carrier drifts under the influence of an applied electric field was measured. Our data indicate that there is a gradient in the collection distance through the material. This gradient in electrical properties has implications for electronic uses of CVD diamond.
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73.61.Cw Elemental semiconductors
73.50.Pz Photoconduction and photovoltaic effects
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
FREE

Self‐organized growth of regular nanometer‐scale InAs dots on GaAs

J. M. Moison, F. Houzay, F. Barthe, L. Leprince, E. André, and O. Vatel

Appl. Phys. Lett. 64, 196 (1994); http://dx.doi.org/10.1063/1.111502 (3 pages) | Cited 531 times

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The deposition of InAs on GaAs proceeds first by two‐dimensional (2D) growth and above a 1.75‐monolayer coverage by the formation of single‐crystal dots on a residual 2D wetting layer. By atomic force microscopy measurements, we show that the first dots formed are in the quantum size range (height 30 Å, half‐base 120 Å), that the dispersion on their sizes is remarkably low (±10%), and that they are located fairly regularly (interdot distance 600 Å). Upon further growth, density and shapes do not change but sizes increase up to double values before coalescence occurs. Self‐organized growth in strained structures is then shown to be a simple and efficient way of building regular quantum dots.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices

717‐mV open‐circuit voltage silicon solar cells using hole‐constrained surface passivation

J. Zhao, A. Wang, A. Aberle, S. R. Wenham, and M. A. Green

Appl. Phys. Lett. 64, 199 (1994); http://dx.doi.org/10.1063/1.111503 (3 pages) | Cited 8 times

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A virtual saturation of the supply of holes leading to an injection level dependent reduction in surface recombination velocity has been shown to be responsible for the improved performance of recent high efficiency silicon solar cells. By fabricating test cells taking advantage of this and other recombination reduction mechanisms, improved open‐circuit voltages of 717 mV have been independently confirmed for experimental silicon cells. These voltages correspond to saturation current densities of 25 fA/cm2 at 25 °C, also the lowest demonstrated for a silicon junction device. Further improvement in both voltage and cell efficiency is expected to result from this work.  
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84.60.Jt Photoelectric conversion
72.40.+w Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Carbon tetrabromide carbon doping of molecular beam epitaxial (GaAs) films

W. E. Hoke, D. G. Weir, P. J. Lemonias, and H. T. Hendriks

Appl. Phys. Lett. 64, 202 (1994); http://dx.doi.org/10.1063/1.111504 (3 pages) | Cited 11 times

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GaAs films were doped with carbon up to a hole concentration of 1.3×1020 cm−3 using CBr4 vapor. The material quality of the heavily doped films was found to be better than that obtained using evaporated carbon. Improvements at the highest doping levels include better surface morphology, higher hole mobilities, significantly stronger photoluminescence, and near unity substitutional incorporation. Doping pulses created using CBr4 exhibited abrupt transitions. From the results it is suggested that the material quality of the films doped with evaporated carbon are degraded at high doping levels due to surface combination of reactive carbon species.
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.72.uj III-V and II-VI semiconductors
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