Russian-armenian state university

RUSSIAN-ARMENIAN STATE UNIVERSITY PHYSICO-TECHNICAL DEPARTMENT Ovsep Emin Str.123,Yerevan, Armenia Prof. Stepan Petrosyan email: [e-mail] Dr. Vladimir Gevorkyan email: [e-mail]

Field of Scientific Activities

• Growth and research of InAsSbP/InAs and Cu2O based heterostructures for photovoltaic and thermophotovoltaic applications

• Development of novel technological methods for the growth of III-V and ZnO nanowires for opto- and microelectronic device applications

• Theoretical and experimental study of high efficiency quantum dot solar cells

• Theory of nanoscale contacts and nanodevices (photodiodes, field-effect transistors, position-sensitive detector)

Relative spectral response of the n+-InAs / n0-InAs / p+- InAs0.27Sb0.23P0.5 TPV diode heterostructure grown by non-equilibrium MOVPE growth technique

Quantum Dot Solar Cell: Structure

Quantum Dot Solar Cell: Results

2D p-n JUNCTION

2D Shchottky contact

2D electron gas field efect transistor

Laser Synthesis of the Colloidal Nanoparticles

• Blue -Ultraviolet Luminescence

• Ultrafine Sizes: 2-3nm

Cancer Therapy&Diagnostics

• Specific labeling of live cells with Quantum Dots

Periodically polled lithium niobate crystals

Wavelength converters based on PPLN

• Another aspect is a strong limitation to the industrial utilization of wavelength converters based on PPLN crystals, which comes from the so called ‘photorefractive effect’, which induces semi-permanent changes in the refractive index under the light illumination. To redress this problem, at present 5mol% magnesium oxide should be incorporated into lithium niobate. But because of the required very high concentration it makes very difficult to grow good optical quality crystal.

• The data obtained by Dr.Kokanyan with co-authors show that tetravalent hafnium ions can be successfully utilized to reduce the photorefractive effect in lithium niobate crystals. Hafnium doping is effective at concentrations much lower than those used with Mg-doping (more than 2 times), potentially allowing crystals with good optical quality and more reproducibly. The micro-Raman results allow assessing a good crystalline quality and a remarkable homogeneity of the Hf-doped lithium niobate crystals.

Laser systems and applications in quantum technologies based on periodically-polled nonlinear crystals

• Periodically-polled nonlinear crystals are very promising for designing of many-line laser systems as well as in areas of applied quantum technologies, including Communication, and Quantum Computation. New laser systems for these goals were theoretically elaborated at Lab. of Quantum Informatics IPR NASA (Prof. Kryuchkyan).

• This activity also includes investigations of new quasi-periodic structures of nonlinear crystals that realize simultaneous frequency-conversion processes within the same crystal.