Preface

9 International Conference «Actual Trends in Radiophysics» in 2021 was held in Tomsk, Russia from 20th to 22th october 2021. International Conference became worthwhile platform for researchers to present their finding in the areas «Physics of radio waves: radiation, reception and use», «radio electronics and electrodynamics of microwave, extremely high frequencies and hyper high frequencies», «Solid-state electronics, micro- and nanoelectronic», «Laser and optoelectronic systems: development, creation, application», «Quantum electronics and photonics», «Modern measuring instruments and technologies», «Modern problems and technologies for training specialists in the field of radiophysics, radio engineering and optics». It aims to provide an international cooperation and exchange platform for experts, scholars and enterprise managers in the fields of the application of radiophysics to share research results, discuss existing problems and challenges and explore cutting-edge technologies. COVID-19 Update: For reasons of Covid 19, the conference changed its time from September 20-22 to October 20-22 and was held in full-time format. This scientific event brings together more than 10 national and international researchers in radiophysics. On top of the local participants coming from different national universities, international participants are also registered from different countries. During the conference, the conference model was divided into seven sessions, including oral presentations, keynote speeches, and Q&A discussion. In the first part, keynote speakers were each allocated 20-30 minutes to hold their speeches. Then in the second part, some scholars, whose submissions were selected as the excellent papers, were given about 10 minutes to perform their oral presentations one by one. List of Program Committee, Organizing Committee, Editorial Committe are available in this pdf.

Quasiadiabatic electron transport in room temperature nanoelectronic devices induced by hot-phonon bottleneck

Since the invention of transistors, the flow of electrons has become controllable in solid-state electronics. The flow of energy, however, remains elusive, and energy is readily dissipated to lattice via electron-phonon interactions. Hence, minimizing the energy dissipation has long been sought by eliminating phonon-emission process. Here, we report a different scenario for facilitating energy transmission at room temperature that electrons exert diffusive but quasiadiabatic transport, free from substantial energy loss. Direct nanothermometric mapping of electrons and lattice in current-carrying GaAs/AlGaAs devices exhibit remarkable discrepancies, indicating unexpected thermal isolation between the two subsystems. This surprising effect arises from the overpopulated hot longitudinal-optical (LO) phonons generated through frequent emission by hot electrons, which induce equally frequent LO-phonon reabsorption (“hot-phonon bottleneck”) cancelling the net energy loss. Our work sheds light on energy manipulation in nanoelectronics and power-electronics and provides important hints to energy-harvesting in optoelectronics (such as hot-carrier solar-cells).

Growth of 100 mm indium antimonide single crystals by modified Czochralski technique

Currently there is a worldwide trend to increase the diameter of crystals grown from elemental semiconductors and semiconductor compounds. According to literary data the diameter of 3–5 semiconductor single crystals grown nowadays is 4 to 6 inches. So far up to 75 mm indium antimonide single crystals have been grown in Russia. Indium antimonide is the element base for the widest field of solid state electronics, i.e., optoelectronics. Indium antimonide is used for the fabrication of 3–5 mm range linear photodetectors and photodetector arrays used as light-sensitive material in heat vision systems. Growth heat conditions have been selected and 100 mm [100] indium antimonide single crystals have been grown using the modified two-stage Czochralski technique. The graphite heating unit has been oversized to accommodate a 150 mm crucible and a 4.5–5 kg load. The results of the work have provided for a substantial increase in the yield of photodetectors. The electrophysical properties of the as-grown single crystals have been studied using the Van der Pau method and proved to be in agreement with the standard parameters of undoped indium antimonide. Using the 9-field etch method of pit counting under an optical microscope the dislocation density in the 100 mm single crystals has been measured to be ≤ 100 cm-2which is similar to that for 50 mm single crystals.

Optothermotronic effect as an ultrasensitive thermal sensing technology for solid-state electronics

The thermal excitation, regulation, and detection of charge carriers in solid-state electronics have attracted great attention toward high-performance sensing applications but still face major challenges. Manipulating thermal excitation and transport of charge carriers in nanoheterostructures, we report a giant temperature sensing effect in semiconductor nanofilms via optoelectronic coupling, termed optothermotronics. A gradient of charge carriers in the nanofilms under nonuniform light illumination is coupled with an electric tuning current to enhance the performance of the thermal sensing effect. As a proof of concept, we used silicon carbide (SiC) nanofilms that form nanoheterostructures on silicon (Si). The sensing performance based on the thermal excitation of charge carriers in SiC is enhanced by at least 100 times through photon excitation, with a giant temperature coefficient of resistance (TCR) of up to −50%/K. Our findings could be used to substantially enhance the thermal sensing performance of solid-state electronics beyond the present sensing technologies.

COMPARISON BETWEEN SINGLE AND DOUBLE INTEGRAL TRANSFORMATION SOLUTIONS OF HEAT CONDUCTION IN SOLID-STATE ELECTRONICS

The design of modern electronic devices has been dealing with challenges on thermal control. In this work, it is proposed two different ways of modeling the temperature field in Solid State Electronics (SSE) using integral transforms, with several heat generations in the domain of the microchip and external convection. Two proposed approaches solve the heat conduction formulation on the SSE using the Classical Integral Transform Technique (CITT): One performing a single transformation (CITT-ST) and the other performing a double transformation (CITT-DT). Both methodologies are compared and achieved similar results. The simpler analytical solution by CITT-DT contrasts with a complex and cumbersome analytical manipulation of CITT-ST. The results show that CITT-ST is more efficient to obtain the solution, requiring a lower truncation order, for the problem of heat conduction in Solid State Electronics even though it has a more complex formulation.

Theoretical Analysis of Experimental Thermoelectric Characteristics of Silicon-Based Whiskers

It is shown that when a conductive crystal with electric field strength and a temperature gradient is placed in a magnetic field with an induction vector , processes of charge and heat carriers transport occur, and they can be described by known generalized electrical conduction and heat conduction equations. The tensors and scalar coefficients that make up these equations are the kinetic properties of crystals. They describe the nature of actual properties of crystals and have a wide pragmatic application in modern solid-state electronics. The process of spatial quantization of the spectrum and its influence on the kinetic properties of crystals is also analyzed.