Prospects for the development of acoustoelectronics

Extensive studies of physical phenomena associated with the interaction of surfactants with electric fields and electrons in piezoelectric dielectrics and semiconductors and piezoelectric – semiconductor layered structures were conducted in 1970–1990s in Europe, the USA, the USSR, Japan, and other countries. This led to the intensive development of acoustoelectronic devices and their use in various electronic information processing and communication systems. In 1974, five European scientists, E. Ash, J. Collins, Y. Gulyaev, K. Ingebrigtsen and E. Paige, were awarded the Hewlett-Packard Prize of the European Physical Society for developing the physical fundamentals of surfactant instruments. Today the nomenclature of acoustoelectronic components on surfactants produced in the world is wide enough. It includes:

- bandpass filters;

- dispersion filters;

- delay lines;

- dispersion delay lines;

- resonators and generators;

- devices for encoding and decoding signals;

- devices for fast Fourier transform;

- Nyquist digital filters;

- frequency synthesizers;

- devices for convolution and correlation of signals;

- sensors, etc.

Band-pass filters for television, stereo radio broadcasting, autoradio, video recorders, CD and DVD players, and in recent years 90% of the market for products on surfactants make cell phones. Among the main enterprises producing acoustoelectronic products are such well-known companies as Murata, Kyoto Ceramics, Fujitsu, Hitachi, NEC, Samsung, Thompson, Vectron, Motorola, Siemens " and many others.

Acoustoelectronics continues to successfully develop as a scientific and technical direction. Every year, under the auspices of IEEE (Institute of Electrical and Electronics Engineers), international conferences on ultrasound, piezoelectrics and frequency control are regularly held, gathering about a thousand participants. The flow of publications and patents does not fall. It is possible to indicate some areas of development that have already been outlined.

• First of all, it is a further improvement and expansion of the scope of matched filters on surfactants, which are now used to recognize coded signals. It seems that such filters will be widely used as markers (tags) for remote identification of any objects - from consumer goods to airplanes, rockets, trains, cars, etc. - up to personal identification.

You can read about devices created on the basis of acoustoelectronics here - T.I. Chernyshova, N.G. Chernyshov, “Designing Filters on Surface Acoustic Waves”, Tambov, Ed. TSTU, 2006.

• Use in acoustic-electronic devices of bulk acoustic waves of very high frequencies (more than 3 GHz), where surfactants are difficult to use due to high absorption in the surface layers. These devices will be represented by high-frequency filters on OAV for wide use in wristwatches, telecommunications and telephony, navigation (GPS), instrumentation, rocket and space technology.

The development of sensor devices on surfactants. Today, surfactant sensors are already used to identify gases, vapors and liquids. In recent years, many new designs of surfactant sensors with increased sensitivity and selectivity have been proposed, including using new types of AB. This opens up new areas of application, including the identification of toxic substances and drugs.

• The fourth direction in the development of acoustoelectronics in subsequent years will be associated with the use of piezoelectric semiconductors or piezoelectric-semiconductor layered structures. You can specify at least six promising surfactant devices based on piezoelectric-semiconductor layered structures:

1. The surfactant amplifier by supersonic drift of electrons of the TWT type. The best result (center frequency 280 MHz, gain 50 dB, noise factor <7, wide band) is comparable to transistor characteristics and suggests that this amplifier will find its niche, especially since it has some advantages, such as full electric isolation of an entrance from an exit.

2. The so-called acousto-injection transistor (AIT), in which the signal gain is achieved by modulating the conductivity of the region between the collector electrodes as a result of the bunching up of electrons by the acoustic wave generated by the input signal. The first experimental results show the promise of this device.

3. Devices with charge transfer acoustic wave (APZS).

4. Convolvers and correlators based on the transverse acoustoelectric effect on surfactants. Emerging new effective designs of these devices allow us to hope for their widespread use for signal recognition and other information processing.

5. Another promising device is an image reading device using short acoustic pulses propagating in a layered structure of a piezoelectric - photosensitive semiconductor and causing a local transverse acoustoelectric effect. This device is in a certain sense an analogue of a vidicon, only instead of an electron beam an acoustic impulse is used.

6. Memory devices that are based on the effect of trapping secondary electrons knocked out by an external pulsed electron beam into the surface layer of a piezoelectric in accordance with the potential distribution in a traveling AB. It looks as if the surfactant "stopped" for some time (hours or days - depending on the residual conductivity of the piezodielectric). Reading the "recorded" information is carried out by applying to the surface of another short pulse of the electron beam, which short-circuits the piezoelectric fields. Existing voltages relax and excite the same surfactant that can be registered by the output transducer.

In conclusion, it can be argued that studying the propagation of acoustic waves in various solids and their interaction with electric and magnetic fields and elementary excitations in such systems will undoubtedly lead to new interesting effects, which, in turn, will give the opportunity for new breakthroughs in the creation high-tech devices and devices.