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18 Oct 1993

Volume 63, Issue 16, pp. 2165-2297

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Measurement of second‐harmonic generation from colored powders

M. Kiguchi, M. Kato, and Y. Taniguchi

Appl. Phys. Lett. 63, 2165 (1993); http://dx.doi.org/10.1063/1.110572 (3 pages) | Cited 7 times

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The second‐harmonic generation with evanescent wave technique was used to measure the efficiency of second‐harmonic generation of an organic colored powder that absorbs the second‐harmonic wave, and it was compared to the electro‐optic coefficient. The refractive index of the sample at the second‐harmonic frequency is complex. The effective refractive index was obtained by measuring reflectivity at the interface between the sample and the prism. This technique is potentially useful for surveying electro‐optic materials.
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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

Improving the thermal stability by anchoring both ends of chromophores in the side‐chain nonlinear optical polymers

Yongqiang Shi, Peter M. Ranon, William H. Steier, Chengzeng Xu, Bo Wu, and Larry R. Dalton

Appl. Phys. Lett. 63, 2168 (1993); http://dx.doi.org/10.1063/1.110573 (3 pages) | Cited 10 times

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We report our study of a new side‐chain second‐order nonlinear optical polymer in which both ends of the chromophores are anchored by thermal crosslinking during electric field poling. A sizable second‐harmonic generation coefficient d33 of 60 pm/V was measured at 1064 nm fundamental wavelength with corona poling. After anchoring both ends of the chromophores, the thermal stability of the poling alignment was greatly improved and the nonlinear optical properties were shown to be stable at both 90 and 125 °C. Channel waveguides were defined in the polymer thin films by reactive ion etching.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Jk Polymers and organics
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

15.9% efficiency solar cells on electromagnetic cold crucible cast multicrystalline silicon

H. E. Elgamel, M. Y. Ghannam, M. R. Murti, J. Nijs, and R. Mertens

Appl. Phys. Lett. 63, 2171 (1993); http://dx.doi.org/10.1063/1.110574 (3 pages) | Cited 5 times

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Hydrogen passivation is found very effective in improving the quality of electromagnetically cased (EMC) multicrystalline silicon from Osaka Titanium Co. (OTC), now Sumitomo Sitix Corp.), due to its small grain size and low oxygen content. A top efficiency of 15.9% is achieved for a 4 cm2 solar cell fabricated on hydrogen passivated EMC‐OTC multicrystalline silicon. Such a result is comparable to the top efficiencies achieved on high quality conventionally casted material and represents the maximum efficiency ever reported for EMC multicrystalline silicon. Fourier transform infrared measurements confirm the low oxygen content in the EMC‐OTC material and spectral response as well as contactless lifetime measurements confirm the role of the plasma hydrogen passivation in substantially improving the diffusion length in this material.
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84.60.Jt Photoelectric conversion
72.40.+w Photoconduction and photovoltaic effects
71.55.Cn Elemental semiconductors

30% external quantum efficiency from surface textured, thin‐film light‐emitting diodes

I. Schnitzer, E. Yablonovitch, C. Caneau, T. J. Gmitter, and A. Scherer

Appl. Phys. Lett. 63, 2174 (1993); http://dx.doi.org/10.1063/1.110575 (3 pages) | Cited 265 times

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There is a significant gap between the internal efficiency of light‐emitting diodes (LEDs) and their external efficiency. The reason for this shortfall is the narrow escape cone for light in high refractive index semiconductors. We have found that by separating thin‐film LEDs from their substrates (by epitaxial lift‐off, for example), it is much easier for light to escape from the LED structure and thereby avoid absorption. Moreover, by nanotexturing the thin‐film surface using ‘‘natural lithography,’’ the light ray dynamics becomes chaotic, and the optical phase‐space distribution becomes ‘‘ergodic,’’ allowing even more of the light to find the escape cone. We have demonstrated 30% external efficiency in GaAs LEDs employing these principles.
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85.60.Jb Light-emitting devices
81.65.-b Surface treatments
78.66.Fd III-V semiconductors

Bistable switching in a nonlinear Bragg reflector

B. Acklin, M. Cada, J. He, and M.‐A. Dupertuis

Appl. Phys. Lett. 63, 2177 (1993); http://dx.doi.org/10.1063/1.110802 (3 pages) | Cited 7 times

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Numerical simulations and experimental results are reported on bistable switching in a semiconductor nonlinear vertical Bragg reflector. An improved structure with an additional linear rear mirror and a phase‐adjusting layer was predicted to have lower threshold for bistability than a Fabry–Perot type device. The experimental observation of bistable switching in a nonlinear Bragg reflector is reported. Achieved threshold was comparable with a nonlinear Fabry–Perot device; the simpler structure of a nonlinear Bragg device may represent an advantage with respect to growth tolerances.
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42.65.Pc Optical bistability, multistability, and switching, including local field effects
42.79.Hp Optical processors, correlators, and modulators
78.66.Fd III-V semiconductors

Electro‐optical characterization of Pb(Zr,Ti)O3 thin films by waveguide refractometry

B. G. Potter, M. B. Sinclair, and D. Dimos

Appl. Phys. Lett. 63, 2180 (1993); http://dx.doi.org/10.1063/1.110576 (3 pages) | Cited 26 times

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Electric field‐induced changes in the extraordinary and ordinary refractive indices of a Pb(Zr0.53Ti0.47)O3 thin film were independently determined using waveguide refractometry. Under an electric field, applied normal to the film plane and corresponding to saturation of the electric polarization, the ratio of the extraordinary to ordinary refractive index change (Δne/Δno) is found to be −4/1, contributing to a net birefringence change [Δ(ne‐no)] of −0.021. Using this technique, both diagonal and off‐diagonal elements of the electro‐optic response tensor describing the macroscopic behavior of the polycrystalline film were accessed, illustrating the importance of this approach in evaluating orientation‐specific electro‐optic characteristics in these films.
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77.80.-e Ferroelectricity and antiferroelectricity
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
78.66.Nk Insulators

Buried heterostructure 0.98 μm InGaAs/InGaAsP/InGaP lasers

E. C. Vail, S. F. Lim, Y. A. Wu, D. A. Francis, C. J. Chang‐Hasnain, R. Bhat, and C. Caneau

Appl. Phys. Lett. 63, 2183 (1993); http://dx.doi.org/10.1063/1.110577 (3 pages) | Cited 4 times

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We report the fabrication and comparison of buried heterostructure and ridge waveguide 0.98 μm lasers with strained InGaAs quantum wells, stepped InGaAsP confinement layers, and InGaP claddings. The buried heterostructure (BH) lasers exhibit superior performance with lower threshold and higher power. We demonstrate a BH laser with 4.4 mA threshold current, 77% differential quantum efficiency, 196 mW of output power, and 150 K characteristic temperature. No catastrophic optical damage is observed on the laser facets, although the facets were not coated or treated.
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42.55.Px Semiconductor lasers; laser diodes
42.60.-v Laser optical systems: design and operation

Influences of iron doping on the photorefractive properties of KTa1−xNbxO3 crystals

Qingcai Guan, Jiyang Wang, Yingwu Lian, Changxing Yang, and Peixian Ye

Appl. Phys. Lett. 63, 2186 (1993); http://dx.doi.org/10.1063/1.110578 (3 pages) | Cited 2 times

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The influences of iron doping on the photorefractive properties of KTa1−xNaxO3 (KTN) crystals were studied. The two‐wave‐mixing gain coefficients and the grating formation rates were measured in undoped and Fe‐doped KTN samples. Photorefractive parameters, such as the effective carrier number density, were determined for these samples. It was shown that the gain coefficient increases significantly with the doped Fe content, but the grating formation rate decreases with it, and that all the influences of iron doping originate mainly from the variation of the effective carrier number density.
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42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Feasibility of room‐temperature operation of tunable coupled‐quantum‐well lasers

M. Ogawa and E. E. Mendez

Appl. Phys. Lett. 63, 2189 (1993); http://dx.doi.org/10.1063/1.110549 (3 pages) | Cited 17 times

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We have calculated the gain of laser heterostructures whose active regions consists of two strongly coupled quantum wells subjected to an electric field. The results demonstrate that by using two 40‐Å GaAs wells separated by an 11‐Å Ga0.7Al0.3As barrier a field‐induced wavelength tunability of over 7 nm is possible at room temperature.
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42.55.Px Semiconductor lasers; laser diodes
42.60.-v Laser optical systems: design and operation

Laser interferometric detection of ultrasonic waves propagating inside a transparent solid

X. Jia, A. Boumiz, and G. Quentin

Appl. Phys. Lett. 63, 2192 (1993); http://dx.doi.org/10.1063/1.110550 (3 pages) | Cited 8 times

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Ultrasonic waves propagating inside a transparent solid have been investigated by using a combination of laser interferometry and photoelastic effect. In comparison with the classical photoelastic technique, the present heterodyne method is sensitive not only to the amplitude but also to the phase of acoustic strains. Pulsed strains of longitudinal, shear, and Rayleigh waves have been experimentally achieved. The phase changes of ultrasonic pulses reflected at the different interfaces were investigated. In addition, the polarization states of shear waves have been observed using the heterodyne detection.
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43.35.Sx Acoustooptical effects, optoacoustics, acoustical visualization, acoustical microscopy, and acoustical holography
43.35.Yb Ultrasonic instrumentation and measurement techniques

Structure of niobium thin films on sapphire

D. F. McMorrow, R. A. Cowley, A. Gibaud, R. C. C. Ward, and M. R. Wells

Appl. Phys. Lett. 63, 2195 (1993); http://dx.doi.org/10.1063/1.110551 (3 pages) | Cited 5 times

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The structure of Nb thin films grown by molecular beam epitaxy on sapphire has been studied using high‐resolution x‐ray scattering techniques. Transverse scans of the x‐ray wave vector transfer through the (110)Nb Bragg peak show diffuse scattering with a Lorentzian‐squared profile, and satellite Bragg peaks for certain orientations of the crystal. The former feature arises from a random, two‐dimensional network of Nb domains, and the latter from a periodic distortion of the Nb films at the terrace edges of the vicinal sapphire substrate.
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68.55.-a Thin film structure and morphology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Structural and electro‐optic properties of pulsed laser deposited Bi4Ti3O12 thin films on MgO

W. Jo, H‐J. Cho, T. W. Noh, B. I. Kim, D‐Y. Kim, Z. G. Khim, and S‐I. Kwun

Appl. Phys. Lett. 63, 2198 (1993); http://dx.doi.org/10.1063/1.110552 (3 pages) | Cited 35 times

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Ferroelectric Bi4Ti3O12 thin films have been grown on MgO (100) and MgO(110) substrates by the pulsed laser deposition. X‐ray diffraction studies show that the films on both substrates have preferential crystallographic orientation such that most of their c axes are close to the substrate normal direction. The film on MgO(110) shows quadratic and hysteretic electro‐optic characteristics with the effective coefficient of about 3.8×10−15 m2/V2.
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81.15.Fg Pulsed laser ablation deposition
77.80.-e Ferroelectricity and antiferroelectricity
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Hydrogenated microcrystalline silicon films produced at low temperature by the hot wire deposition method

R. O. Dusane, Suvarna R. Dusane, V. G. Bhide, and S. T. Kshirsagar

Appl. Phys. Lett. 63, 2201 (1993); http://dx.doi.org/10.1063/1.110801 (3 pages) | Cited 19 times

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In this letter we report the synthesis of hydrogenated microcrystalline silicon at low temperature and without hydrogen dilution of the silane gas by the hot wire method. These films are characterized by higher dark conductivity and larger band gap compared to hydrogenated amorphous silicon. Microcrystallinity in these films is clearly established from the sharp crystalline TO‐like peak in the first‐order Raman spectra. The crystallite size and its volume fraction show a critical dependence on the silane flow rate.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
78.30.Hv Other nonmetallic inorganics

Low‐temperature modifications in the defect structure of amorphous silicon probed by in situ Raman spectroscopy

A. Battaglia, S. Coffa, F. Priolo, G. Compagnini, and G. A. Baratta

Appl. Phys. Lett. 63, 2204 (1993); http://dx.doi.org/10.1063/1.110553 (3 pages) | Cited 12 times

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The modifications occurring in the defect structure of ion implanted amorphous silicon below room temperature have been probed by Raman spectroscopy. Amorphous silicon layers were irradiated at 77 K by 3 keV He+ ions and analyzed in situ by Raman spectroscopy. This low‐temperature ion irradiation produces a shift in the transversal optical (TO) peak position from 471 to 463 cm−1 and a broadening in its halfwidth from 43 to 50 cm−1. Moreover after an annealing at 300 K the vibrational properties come back to their initial state. It is speculated that the modifications induced by low‐temperature ion irradiation are associated with the production and annihilation of highly mobile defects.
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61.80.Jh Ion radiation effects
61.43.Dq Amorphous semiconductors, metals, and alloys
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Mo0.5Si0.5/Si multilayer soft x‐ray mirrors, high thermal stability, and normal incidence reflectivity

H.‐J. Stock, U. Kleineberg, A. Kloidt, B. Schmiedeskamp, Ü. Heinzmann, M. Krumrey, P. Müller, and F. Scholze

Appl. Phys. Lett. 63, 2207 (1993); http://dx.doi.org/10.1063/1.110529 (3 pages) | Cited 11 times

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Multilayer soft x‐ray mirrors with an absorber consisting of the mixture Mo0.5Si0.5 have been fabricated by electron‐beam evaporation in UHV. This has been done to get soft x‐ray normal incidence mirrors for 80–100 eV photon energy with enhanced thermal stability and still high reflectivity. The thermal stability is studied by baking them at temperatures between 600 and 950 °C. The results were compared with multilayers of pure Mo and Si, which were also fabricated by electron‐beam evaporation. After each baking step the x‐ray mirrors are characterized by small angle CuKα x‐ray diffraction. The reflectivity of the first‐order Bragg peak is nearly constant up to 20 min baking at 900 °C. Further we present the normal incidence soft x‐ray reflectivity for wavelengths between 12 and 18 nm of a Mo0.5Si0.5/Si mirror with 12 double layers (N=12) and of a Mo0.5Si0.5/Si mirror as deposited with 33 double layers (N=33). With the latter a reflectivity of 46% is achieved.
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78.70.Ck X-ray scattering
68.60.Dv Thermal stability; thermal effects
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Interface roughness scattering in semiconducting and semimetallic InAs‐Ga1−xInxSb superlattices

C. A. Hoffman, J. R. Meyer, E. R. Youngdale, F. J. Bartoli, and R. H. Miles

Appl. Phys. Lett. 63, 2210 (1993); http://dx.doi.org/10.1063/1.110800 (3 pages) | Cited 35 times

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An analysis of magnetotransport results for InAs‐Ga1−xInxSb superlattices with a range of layer thicknesses demonstrates that interface roughness scattering dominates the electron mobility under most conditions of interest for infrared detector applications. However, the dependence on well thickness is much weaker than the d16 relation observed in other systems with thicker barriers, which is consistent with predictions based on the sensitivity of the energy levels to roughness fluctuations. Theory also correctly predicts an abrupt mobility decrease at the semiconductor‐to‐semimetal transition point, as well as the coexistence of two electron species in semimetallic samples.
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73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Dn Low-field transport and mobility; piezoresistance
78.66.Fd III-V semiconductors

Repetitive excitation of charge oscillations in semiconductor heterostructures

I. Brener, P. C. M. Planken, M. C. Nuss, L. Pfeiffer, D. E. Leaird, and A. M. Weiner

Appl. Phys. Lett. 63, 2213 (1993); http://dx.doi.org/10.1063/1.110530 (3 pages) | Cited 19 times

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We create forced excitonic charge oscillations in semiconductor heterostructures by excitation with periodic optical pulse sequences. The far‐infrared radiation that accompanies the charge oscillations shows temporal interference patterns for pulse sequences with different optical phase profiles, providing evidence for phase induced population transfers between exciton levels in a semiconductor.
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78.47.-p Spectroscopy of solid state dynamics
78.66.-w Optical properties of specific thin films
42.65.-k Nonlinear optics

Free‐standing single‐crystalline chemically vapor deposited diamond films

Y. Tzeng, J. Wei, J. T. Woo, and W. Lanford

Appl. Phys. Lett. 63, 2216 (1993); http://dx.doi.org/10.1063/1.110531 (3 pages) | Cited 18 times

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Free‐standing chemically vapor deposited (CVD) single‐crystalline diamond films have been fabricated by a sequence of processes including high energy ion implantation, microwave plasma enhanced chemical vapor deposition, and the final separation of the diamond epilayer from the substrate by heating in oxygen. The homoepitaxial diamond film separated from the substrate is about 15 μm thick. It is flat and transparent, and exhibits a sharp diamond Raman peak without nondiamond background signals. This process is promising for mass production of large‐area single‐crystalline diamonds with the size restricted only by the availability of one large initial diamond substrate. The initial substrate is expensive but can be used repetitively to produce a large number of single‐crystalline CVD diamond films.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology

Electronic properties of a one‐dimensional channel field effect transistor formed by molecular beam epitaxial regrowth on patterned GaAs

J. H. Burroughes, M. L. Leadbeater, M. P. Grimshaw, R. J. Evans, D. A. Ritchie, G. A. C. Jones, and M. Pepper

Appl. Phys. Lett. 63, 2219 (1993); http://dx.doi.org/10.1063/1.110532 (3 pages) | Cited 9 times

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A high mobility electron gas was grown by molecular beam epitaxy on patterned GaAs consisting of a p‐GaAs/n‐GaAs multilayered structure. By contacting to the p‐GaAs and n‐GaAs layers separately and applying the appropriate bias voltages, we were able to laterally modulate the electron gas to form narrow conduction channels. At 1.5 K we obtain an electron mobility of 5×105 cm2/V s and when operated in the field effect transistor mode a transconductance of 50 ms/mm for a device with a 50‐μm source/drain separation.
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85.30.Tv Field effect devices
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.20.Fr Low-field transport and mobility; piezoresistance

Equilibrium dissociation configuration of misfit dislocations in low strained In0.1Ga0.9As/GaAs single heterostructures

J. Zou and D. J. H. Cockayne

Appl. Phys. Lett. 63, 2222 (1993); http://dx.doi.org/10.1063/1.110533 (3 pages) | Cited 10 times

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Equilibrium dissociation configurations of 60° misfit dislocations in low strained [001] In0.1Ga0.9As/GaAs single heterostructures are investigated by high resolution electron microscopy. The dissociation configuration of misfit dislocations is with the 90° partial being located near the strained interface and the 30° partial lying in the substrate. The equilibrium dissociation width of misfit dislocations has the same value as that in the bulk GaAs material. This equilibrium geometry is explained using the elasticity theory.
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Magnetotunneling spectroscopy in wide In0.53Ga0.47As/In0.52Al0.48As double quantum wells

Jurgen H. Smet, Clifton G. Fonstad, and Qing Hu

Appl. Phys. Lett. 63, 2225 (1993); http://dx.doi.org/10.1063/1.110534 (3 pages) | Cited 15 times

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Magnetoquantum oscillations in the tunnel current of wide In0.53Ga0.47As/In0.52Al0.48As double quantum wells have been exploited to trace the energy levels in the adjacent wells as a function of the applied voltage. The dominant inelastic scattering mechanism was identified as GaAs‐like longitudinal‐optical‐phonon emission. This powerful spectroscopy probe allows an unambiguous identification of the transmission channels responsible for the peaks observed in the current‐voltage characteristics and provides a large number of consistency checks. The obtained experimental results can be used to verify the accuracy of self‐consistent simulation programs.
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73.40.Gk Tunneling
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Nucleation and growth of hydrogenated amorphous silicon‐carbon alloys: Effect of hydrogen dilution in plasma‐enhanced chemical vapor deposition

Yiwei Lu, Ilsin An, M. Gunes, M. Wakagi, C. R. Wronski, and R. W. Collins

Appl. Phys. Lett. 63, 2228 (1993); http://dx.doi.org/10.1063/1.110535 (3 pages) | Cited 5 times

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The microstructural evolution of hydrogenated amorphous silicon‐carbon (a‐Si1−xCx:H) alloy thin films with optical gaps of ∼1.95 eV has been characterized by real time spectroscopic ellipsometry versus hydrogen dilution of the reactive gases (CH4+SiH4) used in plasma‐enhanced chemical vapor deposition. As the H2/(CH4+SiH4) flow ratio is increased to 24, the monolayer‐scale features of nucleation and growth suggest an enhancement in the diffusion length of the film precursors on the substrate and film surfaces, leading to an increase in the surface structural stability and bond‐packing density of the final material. We suggest a causal connection between the monolayer‐scale processes and the ultimate photoelectronic properties of the a‐Si1−xCx:H, which also improve with H2 dilution over the same range.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology
78.66.Jg Amorphous semiconductors; glasses

Forward delay in scaled Al0.48In0.52As/In0.53Ga0.47As heterojunction bipolar transistors

J. A. Baquedano, A. F. J. Levi, B. Jalali, and A. Y. Cho

Appl. Phys. Lett. 63, 2231 (1993); http://dx.doi.org/10.1063/1.110536 (3 pages) | Cited 2 times

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We present experimental measurements and numerical simulations of the intrinsic forward delay as a function of base thickness in abrupt junction n‐p‐n Al0.48In0.52As/In0.53Ga0.47As heterojunction bipolar transistors. For base thicknesses up to 1350 Å and impurity concentration p=1.5×1019 cm−3 we find that nonequilibrium electron transport ensures that base transit delay is less than that in the 3000‐Å‐thick collector space‐charge region. This provides an opportunity to increase base thickness and reduce base resistance without sacrificing the intrinsic forward delay time.
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85.30.Pq Bipolar transistors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Nonconservative formation of 〈100〉 misfit dislocation arrays at In0.2Ga0.8As/GaAs(001) interfaces during post‐growth annealing

Y. Chen, Z. Liliental‐Weber, J. Washburn, J. F. Klem, and J. Y. Tsao

Appl. Phys. Lett. 63, 2234 (1993); http://dx.doi.org/10.1063/1.110537 (3 pages) | Cited 3 times

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Transmission electron microscopy is applied to investigate the effect of annealing on misfit dislocations in an In0.2Ga0.8As/GaAs(001) heterostructure. In as‐grown samples, an orthogonal array of 60° dislocations along 〈110〉 directions is observed in the interface. During annealing, the 60° dislocations along 〈110〉 directions are bent from 〈110〉 directions toward 〈100〉 directions. The process represents a new strain relaxation mechanism in semiconductor heterostructures. As the dislocation segments along 〈100〉 can relieve the strain more effectively than 60° dislocations, we propose that the dislocations move nonconservatively in or near the interface by diffusion along the dislocation cores or in the heterointerface.
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Cc Kinetics of defect formation and annealing
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Photocurrent nonlinearities in ultrafast optoelectronic switches

V. Pašiškevičius, A. Deringas, and A. Krotkus

Appl. Phys. Lett. 63, 2237 (1993); http://dx.doi.org/10.1063/1.110538 (3 pages) | Cited 12 times

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Nonlinearities in photoresponse of ultrafast optoelectronic switches are investigated by using a novel correlation technique. Sublinear behavior is found to be typical for low average electrical fields and superlinear for electrical fields higher than the threshold of electron negative‐differential‐mobility effect. The nonlinearities have been explained in terms of the electrical field redistribution.
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78.47.-p Spectroscopy of solid state dynamics
72.40.+w Photoconduction and photovoltaic effects
85.60.Gz Photodetectors (including infrared and CCD detectors)
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