Definition and field of study of acoustoelectronics

The continuous expansion of the functions of radioelectronic equipment (REA) leads to a sharp complication of the electronic systems themselves and, as a result, to an avalanche-like increase in the number of active and passive components in the systems. Traditional design methods, including the complex miniaturization method based on integrated electronics, cannot solve this problem. A fundamental solution to the problem of increasing quantities of system elements can only be obtained by completely discarding the concepts of classical circuit design and directly using the basic properties of a substance to perform the functions of the system. In this case, these functions are performed without combining the components into systems and without repeatedly increasing their number. These principles are based on the new direction of microelectronics, called functional electronics. One of the most rapidly developing areas of functional electronics is acoustoelectronics.

Acoustoelectronics is the direction of functional microelectronics, based on the use of the piezoelectric effect, as well as phenomena associated with the interaction of electric fields with waves of acoustic voltages in a piezoelectric semiconductor material. Essentially, acoustoelectronics is engaged in the conversion of acoustic signals into electrical and electrical into acoustic. We draw attention to the fact that this definition is similar to the definition of optoelectronics, where it is a question of mutual transformations of optical and electrical signals.

Acoustic (sound) waves (AV) of high frequency (more than 20 kHz) - "ultrasound" - have long been used in various fields of science and technology. Two important properties of AB - a relatively low speed of propagation (105 times less than the speed of light), as well as simplicity and high excitation efficiency in piezoelectric materials - led to their use in radio engineering and electronics. Delay lines on bulk acoustic waves (OAB) have been used in radio engineering for many decades. No less well known are other devices that use OAV in piezoelectric materials, quartz resonators for frequency stabilization. Both of these devices are widely known examples of the use of AB (ultrasound) in electronic systems for processing and transmitting information signals.

In acoustoelectronics, ultrasonic waves are used as volume (longitudinal and shear), and surface, which have several advantages over volume, first of all - small losses during signal conversion, availability of the wave front and a variety of interactions of acoustic waves in crystals.

Since the early 1960s, acoustoelectronics in the narrow sense of the word have begun to call the study of the effects associated with the interaction of AB with free electrons in solids. These effects include:

• "Electronic" absorption of AB.
• The change in the velocity of the AB is due to the interaction with the electron plasma in a solid.
• The "acoustoelectric" effect is a drag of electrons AB and, as a consequence, the appearance of a constant electrical voltage or a constant electrical current in the direction of propagation of the AB.
  
  The first two effects were first investigated by I.G. Shaposhnikov [1] in 1941 and were then studied by many authors (see, for example, reviews [2, 3]). The third effect was discovered by R.G. Parmenter [4] in 1953 and studied in detail by G.E. Bemmel [5], A. B. Pippard [6], G. Weinreich [7], and others (see review [8]).