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7 July 2017

Researchers Exploit Transistor Inefficiencies to Create Advanced Low-Power Temperature Sensor

Temperature-responsive technology has the potential to revolutionise a number of industries, fulfilling such purposes as improving the safety of vehicles, household appliances or just about any other heat-generating technology; for monitoring an individual’s health via constant temperature readouts; or simply making our clothing more capable and adaptable in extreme conditions by adjusting internal heating/cooling systems which are also gaining popularity among consumers.

Especially when it comes to fields such as the aforementioned wearable technology, such sensors do however still possess one major flaw – energy demand. This is exactly the issue a recent project conducted by researchers at UC San Diego has been aiming to fix, and they appear to have had some success.

The team have actually succeeded in creating a prototype sensor which runs on just 113 picowatts of power; that’s approximately 10 billion times less power than a single watt. With such a low energy demand, the new sensors could drastically improve upon the energy efficiency of such devices. The small size of the device will also help in this regard, allowing the systems within the tech to become increasingly compact.

Img: UC San Diego Jacobs School of Engineering
Study author Hui Wang said of the new device, “We’re building systems that have such low power requirements that they could potentially run for years on just a tiny battery.”

The breakthrough was facilitated, somewhat bizarrely, by exploiting a phenomenon regarded by most in the field as a substantial flaw in the design and functionality of transistors.

Transistors within a circuit often feature a gate designed to stop the flow of electrons in said circuit, but as the size of transistors continues to reduce so too does the thickness of the gate material. The thinner this material gets, the more susceptible it becomes to an issue known as ‘gate leakage’, whereby a small number of electrons manage to find their way through the gate regardless of it being closed. It is these leaked electrons which the team are relying upon to power the new sensor.

“Many researchers are trying to get rid of leakage current, but we are exploiting it to build an ultra-low power current source,” said Hui.

By also reducing the power used by the sensor to convert temperature into a digital readout, the team have managed to create a sensor which runs on around 628 times less power than its current competition.

The end result is a near-zero-power sensor with a temperature range of -4°F (-20°C) to 104°F (40°C). The low power usage does come with a slight drawback in the form of less-frequent readouts, around one temperature read per second, but the researchers assert that this should make little difference in the applications in which they envision the sensor being utilised.

The next step for the research team is to focus on making improvements to the sensor’s design, range and accuracy.

Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.