Computer Solid State Physics Laboratory

Victor I. Ryzhii Professor	Irina I.. Khmyrova Assistant Professor	Maxim V. Ryzhii Assistant Professor	Alexander Chaplik Visiting Researcher

The research activity of the Computer Solid State Physics Laboratory is focused on theoretical studies and computer modeling of physical processes in semiconductor micro- and nanostructures and in novel electronic and optoelectronic classical and quantum devices based on such structures. A substantial part of activity of the laboratory is associated with the development of Internet interactive educational resources and materials. Since the laboratory establishment in 1993, its members have published more than 120 journal articles and made more than 120 presentations at international conferences. Among the members of the laboratory there are one Corresponding Member of the Russian (National) Academy of Sciences and three IEEE Senior Members. The research efforts of the laboratory members are now centered on theory and computer modeling of: Semiconductor classical and quantum heterostructure devices operating in the terahertz range of frequencies (terahertz detectors mixers, generators, and photomixers). Quantum-well and quantum-dot infrared photo detectors(QWIPs and QDIPs), QWIP- and QWIP-based functional devices. Electronic and optoelectronic devices based on semiconductor heterostructures with lateral p-n junctions. Theory and computer modeling of zero-resistance and zero-conductance states in two-dimensional electron systems irradiated with microwaves and related phenomena. Original research results obtained in this academic year have been published in refereed journal papers (published in J. Appl. Phys., Jpn. J. Appl. Phys., Physica E, Physical Review, IEEE Trans. On Electron Devices, and others) and presented at different international conferences. The computer Solid State Physics Laboratory conducts research in cooperation with leading research groups at: Kyushu Institute of Technology (Kyoto, Japan), Wayne State University (Detroit, USA), Sensor Electronic Technology, Inc. (Columbia, USA), Ioffe Physical-Technical Institute (St. Petersburg, Russia), Chalmers Institute of Technology (Gothenburg, Sweden), and others.

Refereed Journal Papers

[khmyrova-01:2004]	A. Satou, V. Vyurkov, and I.Khmyrova. Plasma oscillations in terahertz photomixing high-electron-mobility transistor structure on psubstrate. Jpn. J. Appl. Phys., 43:L566-L568., 2004.
[m-ryzhii-01:2004]	M. Ryzhii, V. Ryzhii, and Shur M. Effect of near-ballistic photo electron transport on resonant plasma-assisted photomixing in highelectron mobility transistors. Semicond. Sci. Technol., 19(4):S74-S76, 2004.
	We analyse photomixing using a structure akin to a high-electron mobility transistor. We develop a device model which takes into account the resonant excitation of plasma oscillations in the high-electron mobility transistor and near-ballistic transport of the photogenerated carriers. The transport of the photogenerated carriers is considered using an ensemble Monte Carlo particle modelling. It is shown that the velocity overshoot due to near-ballistic propagation of just photogenerated electrons can substantially increase the efficiency of the resonant photomixing and generation of terahertz radiation.
[m-ryzhii-02:2004]	V. Ryzhii, I. Khmyrova, M. Ryzhii, and Mitin V. Comparison of dark current, responsivity and detectivity of different intersubband infrared photodetectors. Semicond. Sci. Technol., 19(1):8-16, 2004.
	This paper deals with the comparison of quantum well, quantum wire and quantum dot infrared photodetectors (QWIPs, QRIPs and QDIPs, respectively) based on physical analysis of the factors determining their operation.
[m-ryzhii-03:2004]	A. Satou, V. Ryzhii, I. Khmyrova, M. Ryzhii, and M.S. Shur. Characteristics of a terahertz photomixer based on a high-electron mobility transistor structure with optical input through the ungated regions. J. Appl. Phys., 95(4):2084-2089, 2004.
	We develop a device model for a terahertz photomixer that utilizes the excitation of plasma oscillations in the channel of a device similar to a high-electron mobility transistor (HEMT). The device design assumes vertical optical input through the ungated source-gate and gate-drain regions. Using this model, we calculate the characteristics of the HEMT photomixer: the responsivity as a function of the signal frequency for devices with different geometrical and physical parameters, and the dependence of resonant frequency on the length of the gated and ungated portions of the channel and the gate voltage. We compare also the performance of theHEMTphotomixer with that of a similar device but one in which the optical input is through the substrate.
[v-ryzhii-01:2004]	V. Ryzhii, V. Vyurkov, P.O. Vaccaro, and T. Aida. Physics and characteristics of lateral p-n junction tunneling transistor. Physica E, 21(111):867-871, 2004.
[v-ryzhii-02:2004]	V. Ryzhii, R. Suris, and B. B. Shchamkhalova. Mechanisms of absolute negative conductivity in a two-dimensional electron system stimulated by microwave radiation and zero-resistance and zero-conductance states. Physica E, 22(111):13-18, 2004.
[v-ryzhii-03:2004]	Y. Deng, R. Kersting, J. Xu, X.-C. Zhang, M.S. Shur, R. Gaska, G.S. Simin, M. Asif Khan, and V. Ryzhii. Millimeter wave emission from GaN high electron mobility transistor. Appl. Phys. Lett., 84(1):70-72, 2004.
	We report on millimeter wave electromagnetic radiation from a GaN high electron mobility transistor with the gate length of 1.5 um at 8 K. The emission takes place at gate and drain voltages in the linear regime of operation but close to the saturation voltage with the principal emission peak at approximately 75 GHz, which is much higher than the device cut-off frequency. An explanation of this effect involves the 'shallowwater' plasma wave instability, with the frequency of the plasma waves decreased by the ungated regions of the device.
[v-ryzhii-04:2004]	V. Ryzhii. Radiation induced oscollations of the Hall resistivity in two-dimensional electron systems. J. Phys. Soc. Japan, 73(111):1539-1542, 2004.
[v-ryzhii-05:2004]	V. Ryzhii, A. Chaplik, and R. Suris. Absolute negative conductivity and zero-resistance states in two dimensional electron systems: A plausible scenario. Pis'ma v ZhETF (JETP Lett.), 80(111):412-415, 2004.
[v-ryzhii-06:2004]	V. Ryzhii, A. Satou, I. Khmyrova, A. Chaplik, and M.S. Shur. Plasma oscillations in a slot diode structure with a two-dimensional electron channel. J. Appl. Phys., 96(12):7625-7628, 2004.
	We calculate the spectrum of plasma oscillations in a diode structure with a two-dimensional electron channel in a slot between strip-like short circuited contacts. Hydrodynamic electron transport equations coupled with a two-dimensional Poissons equation for the self-consistent electric potential area used. The obtained results can be useful in designing of devices operating at terahertz frequencies based on two-dimensional electron systems and device optimization.

Referred Proceeding Papers

[khmyrova-02:2004]	A. Satou, I.Khmyrova, A. Chaplik, V. Ryzhii, and M. S. Shur. Spectrum of plasma oscillations in a slot diode with a two-dimensional electron channel. In Technical Digest 2004 Int. Conf. on Solid State Devices and Materials (SSDM2004), Tokyo, Japan, Sep. 2004.
[khmyrova-03:2004]	V. Ryzhii, I. Khmyrova, M. Ryzhii, A. Satou, and M. S. Shur. Excitation of terahertz plasma oscillations in a field-effect heterostructure deviceby ultrashort optical pulses: Physics and modeling. In Technical Digest 4th Int. Conf. on Ultrafast Phenomena (UP2004), Niigata, Japan, Jul. 2004.
[khmyrova-04:2004]	V. Ryzhii, A. Satou, I. Khmyrova, M. Ryzhii, T. Otsuji, and M. S. Shur. Analytical and computer models of terahertz HEMT-photomixer. In Technical Digest Photonics Europe, Strasbourg, France, Apr. 2004.
[m-ryzhii-04:2004]	V. Ryzhii, I.Khmyrova, M. Ryzhii, and J.Y. Lin, S.-Y.and Chi. Intersubband infrared photodetectors integrated with field-effect transistors. In K. Kobayashi, editor, 8th Internatonal Symposium on Contemporary Photonics Technology, pages 107-108, Tokyo, Jan. 2005. ES/IEICE, Tokyo Institute of Information and Communication Technology.
	We propose and assess infrared photodetectors bases on the integration of a quantum-well infrared photodetector (QWIP) or a quantum-dot infrared photodetector (QDIP) utilizing electron or hole intersubband transitions and a field-effect transistor (FET).
[m-ryzhii-05:2004]	M. Ryzhii, A. A.Satou, I.Khmyrova, V. Ryzhii, and M.S. Shur. Resonant terahertz photomixers using plasma oscillations: operation, device models, and characteristics. In H.Iwai, editor, Advanced Workshop on 'Frontiers in Electronics' (WOFE 2004), page 56, Aruba, Dec. 2004. IEEE/EDS, Rensselaer Polytechnic Institute.
	We consider operation principle, device models, and characteristics of rezonant terahertz photomixers based on structures akin to high-electron-mobility transistors (HEMTs)and utilizing the excitation of plasma oscillations by the photogenerated electrons and holes.
[m-ryzhii-06:2004]	V. Ryzhii, I. Khmyrova, M. Ryzhii, A. Satou, T. T. Otsuji, and M.S. Shur. Excitation of terahertz plasma oscillations in a field-effect heterostructure device by ultrashort optical pulses: Physics and modeling. In T.Kobayashi, editor, 14th International Conference on Ultrafast Phenomena XIV, pages 147-148, Niigata, July 2004. OSA, OSA.
	We report on the proposal andmodeling of a heterostructure device similar to a field-effect transistor using optical excitation of electron plasma oscillations and intended for generation of terahertz signals.
[m-ryzhii-07:2004]	V. Ryzhii, A. Satou, I. Khmyrova, M. Ryzhii, T. Otsuji, and M.S. Shur. Analytical and computer models of terahertz HEMT-photomixer. In H.Thienpont, editor, SPIE Photonics Europe, pages 5466-24, Strasbourg, Apr. 2004. SPIE, SPIE.
	We develop device models of a terahertz (THz) photomixer based on a high-electron mobility transistor (HEMT) structure utilizing the excitation of electron plasma oscillations in the HEMT channel by the electrons and holes photogenerated by optical signals. We use hydrodynamic equations both for electrons in the channel and for photoelectrons and photoholes in the absorption layer, or hydrodynamic equations for electrons in the channel combined with a kinetic description of the photogenerated carriers, and the Poisson equation for the self-consistent electric field. The models are used for an analytical as well as numerical (based on an ensemble Monte Carlo particle technique) analysis of the HEMT-photomixeroperation in the THz frequency range.

Grants

[m-ryzhii-08:2004]

M Ryzhii. Subsidy of Fukushima Prefectural Foundation for Advancement of Science and Education, 2004-2005.

Academic Activities

[hiroshis-13:2004]	H. Saito, 2004. Member, IPSJ
[khmyrova-05:2004]	Irina Khmyrova, 2004. Senior Member, the Institute of Electrical and Electronics Engineers, USA (1994.03 - to present)
[khmyrova-06:2004]	Irina Khmyrova, 2004. Member, American Physical Society, USA (1995.07 - lifelong membership)
[m-ryzhii-09:2004]	M Ryzhii, March 2004. Senior Member, (1996.01-present), IEEE
[m-ryzhii-10:2004]	M Ryzhii, March 2004. Member, (1995.07-present), American Physical Society
[v-ryzhii-07:2004]	V Ryzhii, March 2004. Corresponding Member, (1987.12-present), Russian Academy of Sciences (Branch of Informatics, Computer Engineering and Automation)
[v-ryzhii-08:2004]	V Ryzhii, Jan. 2004. Fellow (effective from Jan. 2004), IEEE
[v-ryzhii-09:2004]	V Ryzhii, Nov. 2004. Fellow, American Physical Society

Patents

[v-ryzhii-10:2004]

M. Shur, V. Ryzhii, and R. Gaska. Method of radiation generation and manipulation 20040201076 U.S., Oct. 2004.

Ph.D. and Other Theses

[khmyrova-07:2004]	R. Hosoi. Graduation Thesis: Calculation of frequency dependence of the impedance of HEMT-like structures, University of Aizu, 2004. Thesis I. Khmyrova
[khmyrova-08:2004]	Y. Koyama. Graduation Thesis: Study of high-frequency properties of HEMT-like structures, University of Aizu, 2004. Thesis Advisor: I. Khmyrova

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