From an electric guitar to the axial tomograph in the hospital, from the personal computer to video consoles, all current electronic devices work thanks to the properties of crystals. You’ll find semiconductor crystals in chips; piezoelectric crystals in electronic watches, microphones and loudspeakers; pyroelectric crystals in thermographs and alarm systems; and liquid crystals in the displays of mobile phones and televisions. And you’ll find crystals such as graphene or quasicrystals in the materials of the future.
Do you know what crystalline properties are used for this technology? Can you guess how many products that you use every day work thanks to crystals? Would you like to learn how crystals are obtained in industry?
|Silicon chip inside a microprocessor.||Monocrystalline silicon wafer with etched electronic chips.|
Inside every one of the small chips that make our electronic devices work is a tiny sheet of semiconductor crystal with minute circuits etched on the nanoscale that integrate between several hundred and several million electronic components. The crystalline properties of semiconductors in crystalline state make their functioning possible.
It is highly likely that your mobile phone is equipped with an LCD screen. The acronym stands for “Liquid Crystal Display” and its working is indeed based on the light modulation properties that liquid crystals, being crystals, possess. Another screen technology is LED (“Light Emitting Diode”). In this case the image is formed by the light emitted by each pixel, which is a tiny diode of semiconductor crystal. LEDs are more and more present in everyday life, and not only in television screens and mobile phones, but also in advertising boards and even the lamps in our homes.
Telephones are increasingly equipped with sensors that make them “smarter”. They are commonly equipped with compasses, gyroscopes or accelerometers that enable them to know their orientation and movements. In time, other sensors (temperature, humidity, pressure…) will be incorporated. The technology of MEMS allows micro-manufacturing upon crystalline bases of mechanical, thermal, optical and fluidic structures, together with the electronics necessary for its operation.
All digital electronic devices (including the mobile phone) use one or more clocks to set the pace of the electronic circuitry and synchronise their operations. This clock is typically a resonance circuit based on the piezoelectric effect of a quartz crystal. In fact, the corresponding electronic component is colloquially called “crystal” and is the same found in wristwatches, computers, radios and a near-infinity of other electronic devices. The same phenomenon of piezoelectricity is also used to make other devices work, such as microphones and telephone speakers, pickups for musical instruments, sonar and medical ultrasounds.
As well as electronic and mechanical, other properties of crystals are at the basis of current technologies, such as the laser or the components of non-linear optics that enable us to generate or manipulate beams of light.
Solar energy uses silicon crystals, among other materials, and its future depends in large part on finding the cheapest way to produce compound III-V crystals.