Foreign Collaborators

Kim, Eun-Dong, Dr., Electrotechnology Research Institute (KERI), Republic of Korea

№ -0139 Tunable Mid-Infrared Semiconductor Laser in the 2- to 4-micrometer Wavelengths

Full Title:	Tunable Mid-Infrared Semiconductor Laser for High-Resolution Spectroscopic Applications in the 2- to 4-m Wavelengths
Technology Field(s):	INF-ELE: Information and Communications / Microelectronics and Optoelectronics INS-MEA: Instrumentation / Measuring Instruments

Contributors

Yury Pavlovich Yakovlev	A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+2479956; 7+812+2473973 Fax: 7+812+2470006; 7+812+2475416; 7+812+2471017 yak@iropt1.ioffe.rssi.ru
Andrei Popov	A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+2479956 Fax: 7+812+2471017 ap@iropto.ioffe.rssi.ru

Present Status of Research

Brief Description of Research

The laboratory of infrared optoelectronics at Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg has a long and famous history in research and development of semiconductor lasers. Many innovative and striking ideas have been proposed and realized at our institute first. This results in the development and creation of a new family of lasers based on III/V semiconductor compounds and their multicomponent solid solutions (AlGaAsSb, GaInAsSb, InAsSb, InAsSbP, etc).

The first IR single quantum-well laser based on the type II GaInAsSb-GaSb heterojunction was designed and investigated. Recently, this laboratory has advanced in increasing the working temperature of such IR-lasers up to 160K in the pulse regime, and now we have a set of single-mode lasers in the wide spectral range 2.8-3.9 m.

New physical principles of creating of IR-optoelectronic devices were proposed and a set of lasers, light-emitting diodes, photodiodes and avalanche photodiodes for the spectral range 2-4 m operating at room temperature were designed and investigated.

A new thermodynamical approach to liquid-solid and solid-solid phase equilibria was developed in order to determine the region of spinodal decomposition of solid alloys based on GaInAsSb and Al-In-As-Sb. This allowed us to grow high-quality materials with a sharp interface by LPE and to move the red boundary of the emitting structure based on GaInAsSb to the long-wavelength region (up to 2.55 m).

A new type of lasers based on staggered-lineup GaSb-GaInAsSb heterojunctions with self-consistent quantum wells was proposed and realized. This laser can operate due to tunneling-assistant radiative recombination of electrons and holes localized in the quantum well on the type-II interface.

Highly efficient light-emitting diodes based on GaInAsSb/GaSb and GaAlAsSb operating in both the pulse and cw regimes in the spectral range 1.8-2.4 m were fabricated and investigated.

A set of pulse IR lasers, both multimode and single mode, operating in a wide temperature range (1.6-300 K) for the discrete wavelengths in the spectral range 1.7-2.5 m with a total optical pulse power of 100-500 mW was researched and developed. A room temperature CW-operating GaInAsSb laser (2-2.2 m) was made for the first time.

Mid-IR light-emitting diodes (3.0-4.8 m) and laser diodes on the base of InAsSbP/InAs, InAsSb (3.2-3.9 m), were grown and studied. Pulse operating temperature of up to 160 K and cw temperature of up to 100 K were achieved. CW optical power of 5-8 mW was obtained at T = 77K. "Resonant" impact ionization and Auger-recombination was observed experimentally and confirmed theoretically in InAs and GaSb and its alloys having band structures with an energy gap equal to the spin-orbit splitting of the valence band.

The role of a type-II n-n interface has been established in the radiative and non-radiative recombination processes in light-emitting IR diodes, lasers and photodiode structures based on GaSb-GaInAsSb. The temperature dependence of threshold currents of GaInAsSb and InAsSbP lasers was theoretically and experimentally studied, taking into account radiative and non-radiative recombination processes.

A set IR lasers based on GaInAsSb for the spectral range 1.8-2.4 m with pulse power of up to 1 W were developed.

We propose to research and design tunable mid-IR semiconductor lasers based on III-V alloys (InAs-GaSb) for the spectral range 2-4 m operating close to room temperature. New technical approaches will be developed for growing epitaxial laser structures with improved electron and optical confinement and with strain active layers. A theoretical and experimental study of phase equilibrium and miscibility gap in InAsSbP solid solutions lattice-matched with InAs and GaSb substrata will be performed to get wide-gap confinement layers with the highest P content. The physical causes limiting high-temperature operating lasers based on narrow-gap alloys will be discussed. Non-radiative Auger-recombination and carrier heating processes will be theoretically and experimentally considered depending on the band structure of solid solutions, heterobarrier heights and the heterojuction type. Spontaneous and coherent emission of broad area and mesa-stripe lasers with unstrained and strained active layers will be investigated in the temperature range 77-300 K. The temperature dependence of threshold current density for various types of laser structures will be studied both theoretically and experimentally, and the limiting operating temperature of IR lasers based on the InAs alloy will be established. The lasers will developed and adapted to tunable laser diode spectroscopic applications in the mid-infrared range.

Legal Aspects Several Russian Patents have been issued.

Special Facilities

Technological setups for epitaxial growth and post-growth processing of GaSb-InAs multicomponent solid solutions.

Scientific Papers Separate lists are attached.

Foreign Collaborators

University of Montpellier, EM2, France

№ -0140 Application of Ultra-Violet Radiation in IC Nanolithography

Full Title:	The Experimental Technique for Investigation of Applying VUV Radiation in IC Nanolithography
Technology Field(s):	INF-ELE: Information and Communications / Microelectronics and Optoelectronics PHY-OPL: Physics / Optics and Lasers CHE-RAD: Chemistry / Photo and Radiation Chemistry

Contributors

Ruben P Seisyan	A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+2479994; 7+812+2473973 Fax: 7+812+2471017; 7+812+2475416 rseis@ffm.ioffe.rssi.ru
Sergei Vasil'evich Bobashev	A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+2479153; 7+812+2473973; 7+812+2479992 Fax: 7+812+2471017; 7+812+2475416 bobashev@fgd.ioffe.rssi.ru

Present Status of Research

Brief Description of Research

The topological IC image forming an experimental setup that underlies the project concept is based on a projection reflecting an optical system of step-by-step topological image exposition of separate IC layers or of their fragments by a narrow vacuum-ultraviolet (VUV) radiation band selected in the wavelength range from 10 to 120 nm. A VUV source is laser plasma generated by pulsed radiation from a powerful-frequency laser focused on a thin tape (or pellet) made of heavy metal (or gas). The optical system and template (mask) are created on the principles of reflecting X-ray optics with multilayer Bragg`s coating being deposited on estimated-curvature atomic-smooth surfaces (objective or condenser) or on planes (a VUV-mask). Then, an IC image magnified 10 times is engraved on a mask surface with traditional electron-lithography methods by a sharply-focused beam.

The project goal could not be realized without a complex solution of all problems that occur on the way to practical construction of EVUV superlithography, since the nonlinear character of processes proceeding in thin-film materials is determined by all the energy parameters of the radiation flux that affect photoresistance. Thus, the project goals will be achieved with the experimental production of a superlithography design model, which requires that the next problems be solved: - construction of a high-power pulsed frequency laser equipped with a system of effective radiation focusing on a target; - development of an efficient converter with high transformation efficiency and optical tract protection from target fragment contamination; - efficient condenser construction; - construction of projection objective with image correction; - methods of parameter diagnostics and control.

Legal Aspects

Special Facilities

Scientific Papers

S.V. Bobashev and O.S. Vasyutinskii. "Determination of the Elliptical Polarization Parameters of Vacuum Ultraviolet Radiation". Rev. Sci. Instrum. 1992, v.63, n. 1, pp. 1509.

S.V. Bobashev, D.A. Mosesyan, D.M. Simanovskii, and L.A. Shmaenok. "Diagnostics of an Expanding Laser Plasma by Thomson Scattering". Tech. Phys. Lett. 1993, v.19, n. 3, pp.138-139.

M. Hebach, D. Simanovskii, S. Bobashev, and H-J Kunze. "Absolute Measurements of the Soft X-ray Emission from Vacuum Spark Discharges". Plasma Sources Sci. Technol. 1993, v. 2, 296-300.

L. Shmaenok, F. Bijkerk, C. Bruineman, R.K. Bastiaensen, A.P. Shevel'ko, D.M. Simanovskii, A.N. Gladskikh, and S.V. Bobashev. "Developments of a High-Power, Low-Contamination Laser Plasma Source for EUV Projection Lithography". SPIE, Proceedings, 1995, v. 2523, San Diego, pp. 113-121.

S.V. Bobashev, A.V. Golubev, D.A. Mosesyan, Yu.Ya. Platonov, N.N. Salashchenko, D.M. Simanovskii, A.A. Sorokin, and L.A. Shmaenok. "Focusing of Soft X-rays from a Laser-Plasma Source by a Multilayer Mirror". Tech. Phys. 1995, v. 40, n.10, pp. 1011-1016.

L.A. Shmaenok, D.M. Simanovskii, A.N. Gladskikh, and S.V.Bobashev. "Soft X-rays Emitted by a Laser Plasma Created by Two Consecutive Laser Pulses". Techn. Phys. Lett. 1995, v.21, n. 11, pp. 920-922.

D.M. Simanovskii, A.N. Gladskich, L.A. Shmaenok, and S.V.Bobashev. "Demonstration of Laser-induced X-ray Generation in an Expanding Laser-produced Plasma". Phys. Rev. Lett. 1996, v. 77, n. 5, pp. 849-852.

L.A. Shmaenok, Y. Platonov, N.N. Salaschenko, A.A. Sorokin, M.M. Simanovskii, A.V. Golubev, V.P. Belik, S.V. Bobashev, F. Bijkerk, E. Louis, F.G. Meijer, B. Etlisher, and A.Ya. Grudsky. "Multilayer EUV/X-ray Polychromators for Plasma Diagnostiocs". Journ. of Electron Spectr. and Rel. Phenom.1996, v. 80, pp. 259-262.

Foreign Collaborators

Dr. Fred Bijkerk, FOM-Institute for Plasma Physics Rynhuizen, Netherlands.

№-0141 VUV-Excimer Laser and Secondary EVUV Radiation with Thin Inorganic Films

Full Title:	Interaction of Intensive VUV-Excimer Laser Radiation and Secondary EVUV Radiation with Thin Inorganic Films
Technology Field(s):	PHY-OPL: Physics / Optics and Lasers MAT-CER: Materials / Ceramics INF-ELE: Information and Communications / Microelectronics and Optoelectronics

Contributors

Ruben P Seisyan

A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+2479994; 7+812+2473973 Fax: 7+812+2471017; 7+812+2475416 rseis@ffm.ioffe.rssi.ru

Present Status of Research

Brief Description of Research

The aim of this work is to explore physical phenomena occurring with the intense laser radiation of the near ( = 250-120 nm), middle (= 120-20 nm), and far ( = 20-10 nm) vacuum ultraviolet subranges interacting with various thin films and affecting and determining the effect efficiency and spatial resolution when microelectronic product topology including very-large-scale and very-fast-switching integrated circuits (SBIC and SFIC) is being formed. Only high image transfer contrast could be used to compensate for the negative effect of low numerical aperture (on short wavelength) of an optical projection system in IC micro-image formation. The main idea is based on the effect of image transfer contrast magnification discovered in PTI with high energy quanta of electromagnetic radiation interacting with some inorganic films. Strips of 80 nm in width being exposed to 193-nm pulsed radiation of an excimer laser could be resolved, even with contact printing, in spite of a significant sample-mask gap value when Frenel’s zone width exceeds the reproduced band width by more than an order of magnitude. This is evidence that the thin film used as a photo-resistor attains and realizes high-contrast properties. The model of this effect under development also allows us to suggest reliability of high-contrast properties in a wide class of inorganic materials with quantum energy equal to or exceeding that used in the above experiment. The required wavelength range ( = 250-10 nm) is achieved by means of a number of excimer lasers including specific modifications of an excimer laser on inert gas dimers, laser plasma generated by pulsed radiation of a powerful-frequency laser focused on a thin tape (or pellet) made of heavy metal (or gas), and X-ray optics.

This work suggests that we will need to investigate more then 10 oxides, sulfites, nitrides, and some other compounds. The results will be analyzed by spectroscopic and electron-microscopic methods.

Legal Aspects None.

Special Facilities

A stand for micro-lithography with an excimer laser; laser plasma converter setup; X-ray optic elements; electron lithographic complex; spectral, ellipsometric and profile-metering apparatuses; grating microscopes.

Scientific Papers

E.G. Barash, A.Yu. Kabin, V.M. Lyubin, and R.P. Seisyan. Sov. Phys. Tech. Phys 37(3), March 1992.

L.G. Gladysheva, N.A. Kaliteevskaia, R.P. Seisyan, D.V. Smirnov, S.R. Babushkin, and M.A. Vasilevski. Submicron Resolution of Contact Printing by Pulsed Excimer Laser Radiation in Thin Films As₂S₃. SPIE International symposium on Microlithography. Santa Clara, 1996.

L.G. Gladysheva, N.A. Kaliteevskaia, R.P. Seisyan, and D.V. Smirnov. Tech. Phys. Lett. 22(8), August 1996, p. 640-641.

N.A. Kaliteevskaia, R.P. Seisyan, and D.V. Smirnov. Tech. Phys. Lett. 22(8), August 1996, p. 632-633.

Foreign Collaborators

Dr. Richard. H. Stulen, Sandia National Laboratories, USA.

№ -0142 Heterojunction Solar Cells and Thermophotovoltaic Devices Based on A3B5 Compounds

Full Title:	Heterojunction Solar Cells and Thermophotovoltaic Devices Based on A3B5 Compounds
Technology Field(s):	NNE-SOL: Non-Nuclear Energy / Solar Energy PHY-SSP: Physics / Solid State Physics

Contributors

V M Andreev

A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+2479394; 7+812+2473973 Fax: 7+812+2475333; 7+812+2475416; 7+812+2471017 andreev@pcl.ioffe.rssi.ru

Present Status of Research

Brief Description of Research

Investigations in the field of solar cells based on semiconductor compounds were begun at the Ioffe Institute in 1967. Solar cells on the basis of AlGaAs/GaAs heterostructures were developed for the first time at Ioffe in 1969. The photovoltaic laboratory was organized in 1980. Today, the staff consists of 25 people, all devoted to photovoltaics. Areas of investigations are single-junction and tandem solar cells and concentrators modules. Solar-cell development was carried out for AlGaAs/GaAs-, InGaAs/InP- and GaSb-based structures grown by liquid phase epitaxy (LPE) and metal-organic chemical vapor deposition (MOCVD).

High-efficiency (23.5-24.7%, AM0, 20-100 suns) single-junction AlGaAs/GaAs solar cells have been designed and manufactured [1] for modules with concentrators (parabolic troughs and Fresnel lenses). Linear receivers with an efficiency of 18.5-19% have been manufactured for these concentrator modules. Mechanically stacked GaAs/GaSb tandem cells with an efficiency of 28-29% at 100 suns have been fabricated for the linear receivers as well.

Two types of concentrator modules have been designed and manufactured for flight experiments. The first one is based on a 44 Fresnel lens panel and the second is based on parabolic trough and linear Fresnel lens concentrators [2, 3]. An optical efficiency of 93% has been achieved in parabolic trough concentrators, and misorientation curves suitable for space application have been realized in these modules [2]. Diamond-like carbon layers provided effective protection of the Ag coatings of the mirrors: no reduction of the optical efficiency was measured in parabolic trough mirrors in 15 months of usage in the ordinary indoor concentrations. AM0 power density of 230-235 W/m² and specific power of 70-75 W/kg have been achieved in modules based on the parabolic trough concentrators and linear receivers developed.

Monolithic two-junction Al_0.35Ga_0.65As/GaAs solar cells have been designed and manufactured by low-temperature LPE. A connecting tunnel diode was initially prepared by LPE with dopants (Te and Ge) in concentrations as high as 1020cm-3. The following parameters were achieved for the best sample: U_OC = 2.53 V, FF = 0.81 at 50 suns (AM0, 25 °C). Current densities at AM0 (1 sun) are 15.3 mA/cm² in the GaAs subcell and 14.2 mA/cm² in the Al_0.35Ga_0.65As subcell. The combination in one tandem cell of both AlGaAs and GaAs subcells that are highly sensitive will allow as to achieve efficiency values of 30%, which is comparable with these obtained in InGaP/GaAs monolithic tandem solar cells.

Thermophotovoltaic (TPV) devices based on GaSb and InGaAsSb for conversion of infrared radiation from fuel-fired emitters have been produced [1] by LPE and diffusion methods. The maximum efficiency of 11.3% was observed in GaSb cells at 70 suns AM0 concentration. A 1-sun AM0 current density of 45 mA/cm² and UOC = 0.46V at 3.15 A/cm² were achieved in these cells. Lattice-matched In_xGa_1-xAs_ySb_1-y/GaSb heterostructures were grown by LPE from Sb-rich melts. The bandgap energy of InGaAsSb cells was in the range 0.52-0.6 eV, which provides a long-wavelength edge of photosensitivity of 2.15-2.35 m in TPV devices. Monolithic tandem GaSb/InGaAsSb (E_g = 0.56 eV) thermophotovoltaic devices with a connecting tunnel GaSb diode have been developed and produced by the LPE method. Theoretical studies have indicated that current matching of the top (GaSb) and bottom (InGaAsSb) subcells in tandem TPV devices can be realized in the case of bottom subcell bandgap energies of 0.6-0.55 eV for the black-body emitter temperatures of 1100-1500 °C, respectively. External quantum yields of 70-80% in the wavelength range 800-1600 nm (top cell) and about 60% in the range 1800-2100 nm (bottom cell) have been measured in tandem cells. The magnitudes of the U_OC = 0.61V and FF = 0.75 were achieved in one tandem TPV device characterized by a high response up to a wavelength of 2150 nm.

1 MeV, 2 MeV and 3.75 MeV electron and 6.7 MeV proton irradiation tests have been carried out for AlGaAs/GaAs, GaSb, InGaAs and InGaAsSb cells. GaAs-based cells with junction depths of 0.4-0.5 m have a good radiation resistance, comparable to the best published data. GaSb- and InGaAs-based cells have shown radiation resistance comparable with ordinary GaAs-based cells. An improvement in radiation resistance has been achieved in AlGaAs/GaAs solar cells with an internal Bragg reflector. A high stability of the long wavelength spectral response was registered after 3.75-MeV irradiation with electron fluence of 10¹⁶ cm^-2. This effect was obtained due to a reduction in the photoactive n-GaAs layer thickness to 1.5 m with a junction depth of 0.3-0.4 m. Al_0.35Ga_0.65As-based top cells in tandems have also demonstrated higher radiation resistance than in ordinary GaAs-based solar cells.

A set of computerized measurement equipment for characterization of the concentrator solar cells and modules has been designed and manufactured. It includes an installation for recording the absolute values of the solar cell spectral photo-response and reflectivity over the wavelength range of 320-2400 nm and two AM0 flash solar simulators for secondary I-V curves. Spectral photo-response curves can be recorded for both single-junction and tandem cells. Independent verification of the results on solar-cell efficiency and photocurrent at the NASA Lewis Research Center and the Fraunhofer Institute of Solar Energy Systems (Germany) allows us to keep the accuracy of the cell efficiency measurements within the range ±1% (abs).

Expected Research Results

In order to increase efficiency up to more than 30%, new tandem solar structures will be developed. They will consist of an additional narrow bandgap (GaInAsSb or GaSb) solar cell placed under the GaAs-based solar cell. Monolithic AlGaAs/GaAs tandem cells will be prepared by the LPE and MOCVD methods as well.

The forcasted lifetime of the terrestrial power installations developed is more than 15 years. The calculations and experiments show that the specific cost of 1 W of electric power of a terrestrial installation will be less than 3 USD. An production increase to more than 1 MW/year results in a cost reduction down to 2- 2.5 USD per peak watt of installed power.

The new thermophotovoltaic devices with increased efficiency will be developed on the basis of GaSb/InGaAsSb tandem heterostructures that will provide highly efficient conversion of infrared radiation from fuel-fired emitters. Using these cells, generators of electricity (quiet, reliable, clean and efficient) will be developed.

Legal Aspects

Special Facilities

Scientific Papers

1. V.M. Andreev, V.P. Khvostikov, E.V. Paleeva, S.V. Sorokina, and M.Z. Shvarts. "GaAs- and GaSb-Based Solar Cells for Concentrator and Thermophotovoltaic Applications." Proc. of the 25th IEEE PVSC, Washington, DC, May 13-17, 1996, pp.143-146.

2. V.M. Andreev, V.M. Lantratov, V.D. Rumyantsev, and M.Z. Shvarts. "Development of PV Receivers for Space Line-Focus Concentrator Modules." Proc. of the 25th IEEE PVSC, Washington, DC, May 13-17, 1996, pp. 341-344.

3. V.A. Grilikhes, V.D. Rumyantsev, and M.Z. Shvarts. "Indoor and Outdoor Testing of Space Concentrator AlGaAs/GaAs Photovoltaic Modules with Fresnel Lenses." Proc. of the 25th IEEE PVSC, Washington, DC, May 13-17, 1996, pp. 345-348.

Foreign Collaborators

Prof. Yuri Galperin, Department of Physics, University of Oslo, Norway.

№ -0143 Investigation of Heterojunctions by the Acoustic Method

Full Title:	The Investigation of Heterojunctions and Two-Dimensional Gas Interaction by the Acoustic Method
Technology Field(s):	PHY-SSP: Physics / Solid State Physics

Contributors

Irina L’vovna Drichko

A.F.Ioffe Physico-Technical Institute (Ioffe Inst) 26, Polytechnicheskaya str., St Petersburg, 194021, Russia Phone: 7+812+5159229; 7+812+2473973 Fax: 7+812+5156747; 7+812+2475416 irina.l.drichko@shuvpop.ioffe.rssi.ru

Present Status of Research

Brief Description of Research

Our team investigates the surface acoustic wave (SAW) interaction with two-dimensional electron (hole) gas on different heterostructures, such as GaAs/AlGaAs, InGaAs/InP and Si/GeSi. The results of such studies are successfully applied for the investigation of two-dimensional electron localization effects and heterostructure quality determination.

By studying the two-dimensional electron gas interaction with SAW on GaAs/AlGaAs and InGaAs/InP heterosructures, one can determine the kinetic parameters of 2DEG (the carrier density, transport and quantum relaxation time, Dingle temperature) with no contact in the delocalized carrier region.

This method allows one to determine the localization mechanisms in the region of the quantum Hall effect plateaus. The current methods of investigation are useful for the determination of the nonlinearity mechanisms in the localized and delocalized carrier region.

This method can be applied for the investigations of shunting conductivity realized in the three-dimensional layers in the quantum Hall regime, which permits conclusions to be made on the heterostructure quality. The kinetic-effect investigations, especially in the quantum Hall regime, will allow us to enrich the experimental and theoretical achievements of quantum physics of two-dimensional systems and will make it possible to create perfect structures and will give perspective for constructing the new apparatus.

Earlier, such investigations were not applied to study heterostructure parameters.

Legal Aspects None in this research.

Special Facilities None in this research.