Center for Physical Sciemces and Technology, Lithuania

Biography:Prof. Algirdas Sužiedėlis was born in Anjero-Sudzhensk, Russia. He graduated Vilnius University, Department of Physics in 1979. He received PhD degree in Physics from University of Latvia in 1995. Doctor thesis “Properties of l-h junctions with variable cross-section in strong electric fields”. He joined Vilnius Institute of Radiomeasurement Devices in 1979 as an Engineer, Junior research associate and Research associate. In 1992, he joined Semiconductor Physics Institute in Vilnius as an Engineer-physicist, Researcher, Senior researcher and Head researcher. He was the Head of the Laboratory of Nonhomogeneous Structures during 2005-2010. Currently he is Head Researcher at Center for Physical Scie nces and Technology, Head of Laboratory of Semiconductor Structures. Algirdas Sužiedėlis is also Professor at Vilnius Gediminas Technical University. He performed his scientific research at Braun Center for Submicron Research, Weizmann Institute, Israel as visiting scientist (1 month per each 2003, 2004, 2007, and 2008 year). Scientific interests of Prof. Algirdas Sužiedėlis are interaction of microwave radiation with semiconductor nanostructures and rare earth manganites. He is coauthor of more than 170 scientific papers and holds 2 patents. He managed more than 10 National scientific projects, is awarded by Lithuanian State Scientific Prize in 1998.

Speech Title: Sensitive Heterojunction Detectors for Millimetre Waves

Abstract: Recent breakthrough of millimetre waves for commercial high-speed communication and other civil applications promotes the development of cost-effective generators and sensors operating in this range of electromagnetic radiation. Schottky junction diodes are well known as sensitive detectors of electromagnetic radiation and have found wide applications in various fields of microwave electronics. However, high responsivity and good noise properties of low-barrier Schottky diodes are opposed with sensitivity of their electrical properties to ambient conditions and strong dependence of detected signal on frequency. The mentioned drawbacks are determined mostly by the surface location of the Schottky junction. Therefore, search for new design of reliable microwave diodes successfully operating in wide frequency range is relevant to promotion of progress in microwave electronics. Semiconductor heterojunction diode is a promising competitor to the Schottky junction diode. Unlike in the latter, the heterojunction is formed in the bulk of a semiconductor structure what makes the diode less sensitive to the ambient impact and thus more reliable than the Schottky one. In this report we present GaAs/AlGaAs heterojunction microwave diodes of various design developed and investigated by our team: starting from point contact heterojunction diodes for low frequency application and finalizing with planar heterojunction diode on polyimide film designed for operation in the range from microwaves up to infrared radiation. The heterojunction diodes successfully demonstrated detection of both continuous wave signals and pulses of electromagnetic radiation of nanosecond duration in Ka frequency range.

Keywords: millimetre waves, detection, voltage responsivity, heterojunction, semiconductor