Three scientists from the University of Massachusetts Amherst and the Hong Kong University of Science and Technology have developed microcoolers based on AlGaAs superlattices (Applied Physics Letters, July 14, 2003).

Maximum
cooling temperatures of 0.8C and 2C were obtained at 25C and 100C,
respectively. The devices measured 60x60microns. The thermal barriers were
created from 100-period Al0.1Ga0.9As/Al0.2Ga0.8As n-type superlattices. The
team expects the structures to be useful for in situ cooling of GaAs-based
electronic and optoelectronic devices.

Researchers at New York's Rensselaer Polytechnic Institute (RPI) have
created minaturised gas ionisation sensors based on multi-wall carbon
nanotube (MWNT) elements. Ionisation sensors provide fingerprints of
distinct gases but are normally bulky and consume large amounts of power at
high voltages. The MWNT-based sensors use the sharp tips of the tubes to
generate very high electric ionisation fields at relatively low voltages.
The MWNT film was created by chemical vapour deposition (CVD) on a silicon
dioxide substrate.

The high electric fields at the tube tips hasten the breakdown process. The
precise breakdown voltage provides a fingerprint for the particular gas. The
discharge current is determined by the gas concentration. Because the
technique does not involve adsorption/desorption of gases, the sensor
displays a fast response.

The first test in air with an anode-cathode separation of 150microns
generated a 460microA discharge at 346V. Without the nanotubes, the same
structure generates a 69microA current at 960V. Further tests of the
nanotube sensor showed detection capability for helium, argon, nitrogen,
oxygen, carbon dioxide and ammonia.

The team also investigated the use of the sensor for gas chromatography. The
researchers believe that with an appropriate design, analytes in low ppm
range (around 25ppm) could be detected. This could lead to the development
of field-portable gas chromatographs for use in emergencies and
counter-terrorism activities.

AngelTech Live III: Join us on 12 April 2021!

AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST) and will feature online versions of the market-leading physical events: CS International and PIC International PLUS a brand new Silicon Semiconductor International Track!

Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.

2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.

We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.

We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.

Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.

Having attracted 1500 delegates over the last 2 online summits, the 3rd event promises to be even bigger and better – with 3 interactive sessions over 1 day and will once again prove to be a key event across the semiconductor and photonic integrated circuits calendar.

So make sure you sign up today and discover the latest cutting edge developments across the compound semiconductor and integrated photonics value chain.

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