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22 Jul 1996

Volume 69, Issue 4, pp. 443-588

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Observation of compositional modulation in (111)A InGaAs quantum wells and the effect on optical properties

Albert Chin and W. J. Chen

Appl. Phys. Lett. 69, 443 (1996); http://dx.doi.org/10.1063/1.118133 (3 pages) | Cited 5 times

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We have studied the growth of InGaAs/GaAs multiple quantum wells (MQWs) on (111)A GaAs. Uniform thickness of (111)A quantum wells is observed by the cross‐sectional transmission electron microscopy (TEM). Growth induced long‐range In‐ and Ga‐rich InxGa1−xAs/InyGa1−yAs superlattice in (111)A is also observed by cross‐sectional TEM in the ternary InGaAs wells. In contrast, none of the above superstructure was observed by TEM on a side‐by‐side grown (100) oriented substrate. However, the photoluminescence (PL) linewidth is broadened by such compositional modulation. Low‐temperature (15 K) photoluminescence showed a broad PL linewidth of 27.5 meV for In0.16Ga0.84As/GaAs MQWs grown on (111)A substrates at 520 °C. A decreased PL linewidth of 15.7 meV and a reduced compositional modulation in InGaAs wells can be achieved at a higher growth temperature of 560 °C. © 1996 American Institute of Physics.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.66.Fd III-V semiconductors

High‐resolution axial and lateral position sensing using two‐photon excitation of fluorophores by a continuous‐wave Nd:YAG laser

Ernst‐Ludwig Florin, J. K. Heinrich Hörber, and Ernst H. K. Stelzer

Appl. Phys. Lett. 69, 446 (1996); http://dx.doi.org/10.1063/1.118134 (3 pages) | Cited 23 times

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The change in position of fluorescent beads captured inside the focal volume of optical tweezers is monitored using fluorescence emission induced by two‐photon absorption of a continuous‐wave Nd:YAG laser (λ=1064 nm). The displacement of a bead due to interactions with its environment leads to a fluorescence intensity variation that is used to design a novel spatial sensor. We determine changes in the axial position of a CY3‐labeled latex bead with a diameter of 1.03 μm to a precision better than 10 nm. At an intensity of 600 mW/ μm2 the two‐photon bleaching rate is lower than 50% per 2000 s. © 1996 American Institute of Physics.
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07.60.Pb Conventional optical microscopes
42.62.Be Biological and medical applications
87.80.-y Biophysical techniques (research methods)

Quantum boxes as active probes for photonic microstructures: The pillar microcavity case

J. M. Gérard, D. Barrier, J. Y. Marzin, R. Kuszelewicz, L. Manin, E. Costard, V. Thierry‐Mieg, and T. Rivera

Appl. Phys. Lett. 69, 449 (1996); http://dx.doi.org/10.1063/1.118135 (3 pages) | Cited 114 times

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A GaAs/AlAs planar cavity containing a collection of InAs quantum boxes in its core region has been grown in a single step by molecular beam epitaxy, and processed by electron‐beam lithography and reactive ion etching into pillar microresonators. The optical study by photoluminescence of these localized light emitters allows a systematic and precise determination of the energies of the first confined photon modes of such microstructures, in good agreement with theoretical estimates. More generally, such probes facilitate the experimental study of the modes of complex photonic microstructures and of the spontaneous emission alteration they entail on a quasimonochromatic light emitter. © 1996 American Institute of Physics.
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42.55.Sa Microcavity and microdisk lasers
78.66.Fd III-V semiconductors
42.82.Cr Fabrication techniques; lithography, pattern transfer

A vacuum ultraviolet flash lamp with extremely broadened emission spectra

Shoichi Kubodera, Mitsuo Kitahara, Junji Kawanaka, Wataru Sasaki, and Kou Kurosawa

Appl. Phys. Lett. 69, 452 (1996); http://dx.doi.org/10.1063/1.118136 (3 pages) | Cited 10 times

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We have developed a vacuum ultraviolet (VUV) flash lamp using a binary rare gas mixture excited by a pulsed silent discharge. In a Kr/Xe silent discharge, the VUV emission spectral width was extended up to 26 nm full width at half‐maximum (FWHM) at a center wavelength of 162 nm. According to kinetic analyses, such a spectral extension in mixed rare gases is attributed to the simultaneous emissions from heteronuclear rare gas excimers (KrXe∗) and homonuclear rare gas excimers (Kr2∗ and Xe2∗). © 1996 American Institute of Physics.
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42.72.Bj Visible and ultraviolet sources
52.80.Yr Discharges for spectral sources (including inductively coupled plasma)

Reduced temperature sensitivity of the wavelength of a diode laser in a stress‐engineered hydrostatic package

Daniel A. Cohen, Mark E. Heimbuch, and Larry A. Coldren

Appl. Phys. Lett. 69, 455 (1996); http://dx.doi.org/10.1063/1.118137 (3 pages) | Cited 7 times

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By using the effects of increasing hydrostatic pressure to counteract the effects of rising temperature, we demonstrate a technique to stabilize the wavelength of an uncooled diode laser. We use the differential thermal expansion between various materials incorporated into the laser package to automatically generate a temperature‐dependent pressure, and obtain a 50% reduction in the temperature sensitivity of the wavelength of a 1.55 μm GaInAsP/InP laser. © 1996 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
68.70.+w Whiskers and dendrites (growth, structure, and nonelectronic properties)

Nonlinear optical properties of lanthanum doped lead titanate thin film using Z‐scan technique

Qingchun Zhao, Yun Liu, Wensheng Shi, Wei Ren, Liangying Zhang, and Xi Yao

Appl. Phys. Lett. 69, 458 (1996); http://dx.doi.org/10.1063/1.118138 (2 pages) | Cited 20 times

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Lanthanum doped lead titanate (PLT) thin films with good surface morphology and perovskite structure were fabricated by the metalo‐organic decomposition process. Their nonlinear optical property was investigated by Z‐scan technique. PLT30 thin films on the quartz substrate display strong nonlinear optical effects. A nonlinear refractive index as high as 3.0×10−7 esu was obtained for the thin film. All the results show that PLT ferroelectric thin films are promising materials for nonlinear optics. © 1996 American Institute of Physics.
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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

Interdiffusion as a means of fabricating parabolic quantum wells for the enhancement of the nonlinear third‐order susceptibility by triple resonance

E. Herbert Li

Appl. Phys. Lett. 69, 460 (1996); http://dx.doi.org/10.1063/1.118139 (3 pages) | Cited 6 times

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Interdiffusion of a standard AlGaAs/GaAs quantum well is proposed as a viable alternative to the complex techniques necessary to fabricate parabolic quantum wells. The extent of the linear diffusion is optimized in order to produce an energy‐level ladder if four almost equally spaced eigenstates. The calculated third‐order susceptibility of 2700 (nm/V)2 is comparable with that of the parabolic quantum well, which is more than six orders of magnitude compared to that of the bulk GaAs. © 1996 American Institute of Physics.
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42.65.An Optical susceptibility, hyperpolarizability
66.30.Ny Chemical interdiffusion; diffusion barriers
42.82.Cr Fabrication techniques; lithography, pattern transfer

Reduction of the thermal impedance of vertical‐cavity surface‐emitting lasers after integration with copper substrates

D. L. Mathine, H. Nejad, D. R. Allee, R. Droopad, and G. N. Maracas

Appl. Phys. Lett. 69, 463 (1996); http://dx.doi.org/10.1063/1.118140 (2 pages) | Cited 14 times

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Vertical‐cavity surface‐emitting lasers (VCSELs) have been transferred from their original GaAs substrates to Cu substrates and continuous wave operation has been obtained on the VCSELs after epitaxial transfer. The resultant measurements show a doubling of the output power and a 20% reduction in the thermal impedance. Increased optical power is explained by improved thermal heat sinking as measured from the lasing spectra of horizontal‐cavity edge‐emitting lasers fabricated from the same VCSEL material. © 1996 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.82.Cr Fabrication techniques; lithography, pattern transfer

InAsSb‐based mid‐infrared lasers (3.8–3.9 μm) and light‐emitting diodes with AlAsSb claddings and semimetal electron injection, grown by metalorganic chemical vapor deposition

A. A. Allerman, R. M. Biefeld, and S. R. Kurtz

Appl. Phys. Lett. 69, 465 (1996); http://dx.doi.org/10.1063/1.118141 (3 pages) | Cited 40 times

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Gain‐guided, injection lasers using AlAsSb for optical confinement and a strained InAsSb/InAs multiquantum well active region were grown by metalorganic chemical vapor deposition. The semi‐metal properties of a p‐GaAsSb/n‐InAs heterojunction are utilized as a source for injection of electrons into the active region of the laser. In pulsed mode, the laser operated up to 210 K with an emission wavelength of 3.8–3.9 μm. We also report on the two‐color emission of a light‐emitting diode with two different active regions to demonstrate multistage operation of these ‘‘unipolar ’’ devices. © 1996 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
85.60.Jb Light-emitting devices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Optical properties of defects in ion implanted silicon carbide probed at λ=633 nm

P. Musumeci, L. Calcagno, M. G. Grimaldi, and G. Foti

Appl. Phys. Lett. 69, 468 (1996); http://dx.doi.org/10.1063/1.118142 (3 pages) | Cited 11 times

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The damage produced in silicon carbide single crystal by ion implantation was investigated by in situ optical transmittance and reflectance at 633 nm and by Rutherford backscattering channeling spectroscopy. Implantations were performed at room temperature with different ions (He, N, Ar, Kr, and Xe) in the fluence range 1011–2.5×1016 ions/cm 2. During irradiation a reduction of transmittance and a contemporary increase of reflectance occurred. RBS indicated a continuous accumulation of damage within a depth comparable with the ion range until the formation of an amorphous layer. A combination of optical and RBS data allowed to correlate the optical constant (n,k) to the damage produced during irradiation. Such a correlation was identical for every ion pointing out that the optical properties of the damaged material are independent of the energy density inside the single cascade. © 1996 American Institute of Physics.
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61.80.Jh Ion radiation effects
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.72.up Other materials

Laterally oxidized long wavelength cw vertical‐cavity lasers

Near M. Margalit, Dubravko I. Babic, Klaus Streubel, Richard P. Mirin, Dan E. Mars, John E. Bowers, and Evelyn L. Hu

Appl. Phys. Lett. 69, 471 (1996); http://dx.doi.org/10.1063/1.118143 (2 pages) | Cited 17 times

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We report a novel long wavelength(1.55 μm) vertical cavity laser using a current constricting AlAs oxidation layer. The devices exhibit record low room temperature continuous wave (cw) threshold current(1.3 mA) and highest cw operating temperature reported for long wavelength VCLs(39 °C). Wafer fusion is used to combined seven strain compensated InGaAsP wells between two Al(Ga)As/GaAs quarter wave mirrors. © 1996 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
78.66.Fd III-V semiconductors

Laser‐plasma interaction during visible‐laser ablation of methods

Jim J. Chang and Bruce E. Warner

Appl. Phys. Lett. 69, 473 (1996); http://dx.doi.org/10.1063/1.118144 (3 pages) | Cited 51 times

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We have investigated the dynamics of high‐radiance visible‐laser interaction with a metal vapor plasma during laser ablation of aluminum and carbon steel. The experiment with a copper vapor laser reveals strong plasma‐absorption induced ignition at laser intensities above 1–2 GW/cm2. Approximation based on hydrodynamic relations indicates that the vapor density at the end of the 40‐ns laser pulse is 3×1020–1×1021 cm −3 with a pressure of a few thousand atmosphere at the target surface. This high‐density vapor with a temperature exceeding 10 000 K leads to pronounced plasma absorption via photoionization. Plasma absorption via inverse bremsstrahlung is determined to be negligible because of a relatively low electron density, measured to be peaked at ∼5×1018 cm−3.
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52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
79.20.Ds Laser-beam impact phenomena

Vacuum arc discharges preceding high electron field emission from carbon films

O. Gröning, O. M. Küttel, E. Schaller, P. Gröning, and L. Schlapbach

Appl. Phys. Lett. 69, 476 (1996); http://dx.doi.org/10.1063/1.118145 (3 pages) | Cited 65 times

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Field emission measurements on chemical vapor deposition diamond and laser ablated a‐C films show an activation step after reaching a certain critical electric field. At this field a vacuum arc of some hundred ns duration initiates. While high current arcing leads to the evaporation of the spot surface melting, amorphization or cracking of the film is encountered for lower currents. In any case, much higher electron emission can be observed after this activation procedure due possibly to tip formation resulting in an electric field enhancement. By using a 1 GΩ resistance the discharge current can be limited nevertheless, an activation is observed. © 1996 American Institute of Physics.
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79.70.+q Field emission, ionization, evaporation, and desorption
52.80.Vp Discharge in vacuum

Near infrared absorption and dark conductivity of K1−yLiyTa1−xNbxO3 crystal

Xiaolin Tong, Min Zhang, Amnon Yariv, Aharon Agranat, Rudolf Hofmeister, and Victor Leyva

Appl. Phys. Lett. 69, 479 (1996); http://dx.doi.org/10.1063/1.118146 (3 pages) | Cited 7 times

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Absorption bands in the wave‐number range of 3525–3470 cm−1 have been observed in K1−yLiyTa1−xNbxO3 (KLTN) doped crystals except in crystals doped with Cu and V. These absorption bands are attributed to the O–H vibration band. The hydrogen concentration in KLTN doped crystal is controllable either by doping or by heat treatment. The activation energy of hydrogen ion migration is between 0.6 and 0.7 eV in KLTN doped crystals. The [H +] ion is identified as responsible for fixing (screening) the holographically produced electronic grating. © 1996 American Institute of Physics.
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78.30.Hv Other nonmetallic inorganics
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
66.30.H- Self-diffusion and ionic conduction in nonmetals

Photoinduced synthesis of amorphous SiO2 with tetramethoxysilane

Koichi Awazu and Hideo Onuki

Appl. Phys. Lett. 69, 482 (1996); http://dx.doi.org/10.1063/1.118147 (3 pages) | Cited 10 times

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Photoinduced fabrication of amorphous SiO2 (a‐SiO2) film is examined with tetramethoxysilane (TMOS) at room temperature. The photoinduced reactions consist of two steps: photoexcitation of silicon substrate and photoinduced synthesis of a‐SiO2. The surface of the irradiated silicon with the Xe2 excimer lamp peaking at 7.2 eV is covered with silanol groups. Although the TMOS is difficult to coat on a silicon substrate because of its high volatility, the TMOS can be coated on the irradiated silicon wafer. The increase of the cohesive power is thought to originate from silanol groups on silicon generated with irradiation. Infrared absorption related to the methyl group in TMOS disappeared with illumination in the second step. The line shape of IR absorption turns to be similar to that of thermal SiO2 on silicon. The dependence of photon energy for illumination is also examined. The refractive index of SiO2 synthesized from TMOS is 1.453 at 633 nm, which is almost the same as the refractive index of thermal SiO2. Finally, a model of photochemical reaction is proposed. © 1996 American Institute of Physics.
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42.70.Ce Glasses, quartz
82.50.Bc Processes caused by infrared radiation
82.50.Hp Processes caused by visible and UV light
78.66.Nk Insulators

Effects of hydrogen surface pretreatment of silicon dioxide on the nucleation and surface roughness of polycrystalline silicon films prepared by rapid thermal chemical vapor deposition

Y. Z. Hu, C. Y. Zhao, C. Basa, W. X. Gao, and E. A. Irene

Appl. Phys. Lett. 69, 485 (1996); http://dx.doi.org/10.1063/1.118148 (3 pages) | Cited 14 times

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It is well known that Si surface treatment is crucial for low‐temperature Si epitaxy. Although considerable work exists which is aimed at elucidating the effects of Si surface pretreatments on Si epitaxy, little is known about the effects of SiO2 surface pretreatments for polycrystalline silicon (poly‐Si) growth. We report on a study of SiO2 surface pretreatment effects on poly‐Si nucleation and film surface roughness using a low energy hydrogen ion beam (200 eV) and H2 gas annealing (850 °C) in a rapid thermal chemical vapor deposition system. In situ real‐time ellipsometry was used to monitor the surfaces during pretreatment and observe the nucleation. The microstructure and surface roughness of the deposited poly‐Si films are determined by analysis of in situ spectroscopic ellipsometry (SE) and atomic force microscopy (AFM) measurements. Hydrogen ion beam pretreatment was found to produce higher nuclei density and a smoother poly‐Si surface than nonpretreated substrates, and the opposite was found for hydrogen gas annealing giving lower nuclei density and rougher poly‐Si. © 1996 American Institute of Physics.
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68.55.-a Thin film structure and morphology
81.05.Cy Elemental semiconductors
81.65.-b Surface treatments
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

High resolution imaging of electronic devices via x‐ray diffraction topography

W. T. Beard, K. A. Green, X.‐J. Zhang, and R. W. Armstrong

Appl. Phys. Lett. 69, 488 (1996); http://dx.doi.org/10.1063/1.117762 (3 pages) | Cited 1 time

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Measurements are reported for x‐ray diffraction topography (XRDT) images of implantation and superstructure details in an integrated circuit device investigated with the reflection method of line modified‐asymmetric crystal topography (LM‐ACT). The x‐ray penetration depth and the micron grain size of thin‐film nuclear emulsions used to record the diffraction images are shown to limit spatial resolution in the x‐ray topographs. © 1996 American Institute of Physics.
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61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
61.05.cm X-ray reflectometry (surfaces, interfaces, films)
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
85.30.De Semiconductor-device characterization, design, and modeling

Nanocrystallites in tetrahedral amorphous carbon films

S. Ravi, P. Silva, Shi Xu, B. X. Tay, H. S. Tan, and W. I. Milne

Appl. Phys. Lett. 69, 491 (1996); http://dx.doi.org/10.1063/1.117763 (3 pages) | Cited 28 times

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The microstructure of filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films is studied as a function of ion energy. An optimum energy window in the density and C–C  sp3 content at an ion energy of ∼90 eV observed in this study. It is shown that the density of the amorphous carbon films are closely related to the sp3 content. The observation of nanocrystals embedded in the amorphous carbon matrix is reported. Most of the crystals observed by transmission electron microscopy can be indexed to graphite, but some of the crystals can be indexed to cubic diamond. The chemical composition of the crystals is analyzed using electron energy loss spectroscopy (EELS). The only discernible EELS edge is that of C at an energy of 285 eV. © 1996 American Institute of Physics.
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68.55.-a Thin film structure and morphology
61.43.Dq Amorphous semiconductors, metals, and alloys
61.46.-w Structure of nanoscale materials

Epitaxial growth of ultrathin Si caps on Si(100):B surface studied by scanning tunneling microscopy

Z. Zhang, M. A. Kulakov, B. Bullemer, I. Eisele, and A. V. Zotov

Appl. Phys. Lett. 69, 494 (1996); http://dx.doi.org/10.1063/1.117764 (3 pages) | Cited 6 times

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Epitaxial growth of extremely thin Si films (few monolayers) is studied by scanning tunneling microscopy. Using specific boron‐induced surface features as an indication of the presence of boron on the surface, boron segregation to the surface is tested both in solid phase epitaxy and molecular beam epitaxy regimes. The results show that under appropriate conditions there is no indication on boron segregation even on atomic scale. © 1996 American Institute of Physics.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
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
81.15.Np Solid phase epitaxy; growth from solid phases

Ion assisted growth of diamond

S. Sattel, J. Robertson, M. Scheib, and H. Ehrhardt

Appl. Phys. Lett. 69, 497 (1996); http://dx.doi.org/10.1063/1.117765 (3 pages) | Cited 10 times

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Diamond crystallites up to 40 nm in size have been grown from a highly ionized plasma beam of acetylene for ion energies close to 100 eV per C atom and substrate temperatures above 450 °C. This shows that diamond can be grown by physical vapor deposition from an ion‐rich plasma as well as by chemical vapor deposition from a radical‐rich plasma. The formation mechanism is argued to be one of nucleation and growth rather than a stress induced transformation from graphite. © 1996 American Institute of Physics.
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81.15.Jj Ion and electron beam-assisted deposition; ion plating
81.05.ub Fullerenes and related materials
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Current self‐oscillations in photoexcited type‐II GaAs‐AlAs superlattices

M. Hosoda, H. Mimura, N. Ohtani, K. Tominaga, T. Watanabe, K. Fujiwara, and H. T. Grahn

Appl. Phys. Lett. 69, 500 (1996); http://dx.doi.org/10.1063/1.117766 (3 pages) | Cited 12 times

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Self‐oscillations of the photocurrent have been observed in type‐II GaAs‐AlAs superlattices. In addition to the fundamental frequency, several higher harmonics are present. The frequency of the oscillations can be tuned for a fixed carrier density from 15 to 120 MHz by simply changing the applied bias. The frequency distribution within a certain voltage range can be varied by changing the density of photoexcited carriers. For larger carrier densities, higher frequencies are observed in a different voltage range. This system could therefore be used as a high‐frequency oscillator, which can be controlled by two external parameters, the applied voltage and the light intensity. © 1996 American Institute of Physics.
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73.50.Fq High-field and nonlinear effects
73.40.Gk Tunneling
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Gallium vacancies and the yellow luminescence in GaN

Jörg Neugebauer and Chris G. Van de Walle

Appl. Phys. Lett. 69, 503 (1996); http://dx.doi.org/10.1063/1.117767 (3 pages) | Cited 406 times

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We have investigated native defects and native defect‐impurity complexes as candidate sources for the yellow luminescence in GaN. Using state‐of‐the‐art first‐principles calculations, we find strong evidence that the Ga vacancy (VGa) is responsible. The dependence of the VGa formation energy on Fermi level explains why the yellow luminescence is observed only in n‐type GaN. The VGa defect level is a deep acceptor state, consistent with recent pressure experiments. Finally we show that the formation of VGa is enhanced by the creation of complexes between VGa and donor impurities. © 1996 American Institute of Physics.
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61.72.Bb Theories and models of crystal defects
61.72.J- Point defects and defect clusters
78.60.-b Other luminescence and radiative recombination

Passivation of Si(111)‐7×7 by a C60 monolayer

A. W. Dunn, P. Moriarty, M. D. Upward, and P. H. Beton

Appl. Phys. Lett. 69, 506 (1996); http://dx.doi.org/10.1063/1.117768 (3 pages) | Cited 14 times

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C60 monolayers are formed on a Si(111)‐7×7 surface under ultrahigh vacuum (UHV) conditions. The effects of exposure to atmosphere (for 30 min) and water (for 30 s) are assessed by comparing images of the surface acquired using an UHV scanning tunneling microscope. Following exposure and/or immersion we are able to resolve the C60 molecules exhibiting hexagonal order in an arrangement which is essentially identical to that formed prior to withdrawal from the UHV system. Our results clearly show that deposition of one monolayer of C60 on a Si surface can inhibit chemical attack by water and atmospheric oxygen. © 1996 American Institute of Physics.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
61.48.-c Structure of fullerenes and related hollow and planar molecular structures
81.65.Rv Passivation

He‐plasma assisted epitaxy for highly resistive, optically fast InP‐based materials

D. B. Mitchell, B. J. Robinson, D. A. Thompson, Li Qian, S. D. Benjamin, and P.W. E. Smith

Appl. Phys. Lett. 69, 509 (1996); http://dx.doi.org/10.1063/1.117769 (3 pages) | Cited 6 times

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InP and related quaternaries (InGaAsP) have been grown by conventional gas source molecular beam epitaxy while simultaneously exposing the growth surface to a He plasma stream generated by electron cyclotron resonance. For growth temperatures from 400 to 450 °C, the InP produced by this process displays greatly increased resistivity, as high as 105 Ω cm, compared to growth without plasma where resistivities are typically less than 1 Ω cm. An InGaAsP quaternary, with band‐gap wavelength of 1.55 μm, grown with the plasma displays a sharp band edge and fast photoresponse (15 ps). © 1996 American Institute of Physics.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.66.Fd III-V semiconductors
73.61.Ey III-V semiconductors

Optical effect on thermal emission of semiconductors

G. Chen

Appl. Phys. Lett. 69, 512 (1996); http://dx.doi.org/10.1063/1.117770 (2 pages) | Cited 2 times

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Emissivity is generally considered as a material property that depends on the temperature and the surface condition of the sample. This letter will demonstrate that the thermal emission and, thus, the emissivity of a semiconductor wafer heated by a radiation source depends not only on the wafer temperature but also on the radiation heater. The observed phenomenon is explained through electron‐hole excitation in the wafer by the photons emitted from the heater. Such an optical effect may affect the interpretation of the measurement of the temperature dependence of the optical properties of semiconductors and limit the accuracy of temperature measurement of semiconductors by infrared pyrometry. The finding also has important implications for the thermal modeling of semiconductor manufacturing processes such as rapid thermal processing. © 1996 American Institute of Physics.
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78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
44.40.+a Thermal radiation
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