Supersensitive microelectronics
The invention promises smaller and cheaper sensors for many potential applications
NUS scientists have created a magnetic sensor 200 times more sensitive than most commercially available products. This means smaller and lower-cost sensors that can potentially be used in areas such as consumer electronics, information and communication technology, biotechnology and automotive applications.
Headed by Associate Professor Yang Hyunsoo of NUS Electrical and Computer Engineering, the team developed the new sensor from graphene and boron nitride. Comprising a few layers of carrier-moving channels controlled by a magnetic field, the hybride sensor shows much higher sensitivity than current silicon and indium antimonide products.
When measured at 127 degree Celsius - the maximum temperature which most electronics products operate the hybride sensor recorded a sensitivity gain of more than eight-fold over other reported laboratory results, and more than 200 times that of sensors in the market. It also showed little temperature dependence from room temperature to 127 degree Celsius, making it ideal for hot environments.
Another major discovery is that the mobility of the graphene multilayers enables the sensor's characteristics to be optimised by tuning the voltage across it. This control gives the material an advantage over existing sensors.
The breakthrough work, which promises cheaper sensor production by eliminating expensive wafers, was published in Nature Communications in September.
Assoc Prof Yang, who is also attached to the NUS Nanoscience and Nanotechnology Institute (NUSNNI) and the Centre for Advanced 2D Materials (CA2DM), pointed out that magnetic sensors are everywhere, from home appliances to "counters that track the number of vehicles in parking lots and drive-throughs. For instance, a car alone can have up to 30 magnetic sensors to monitor speed, pressure and position, as well as other functions.
Current sensors' properties can change due to air-conditioning or heat from the sun, requiring a temperature correction mechanism which incurs more cost. The NUS innovation avoids these issues, allowing for tinier and cheaper electronics. "Our sensor is perfectly poised to pose a serious challenge in the magnetoresistance market by filling the performance gaps of existing sensors, and finding applications as thermal switches, hard drives and magnetic field sensors. Our technology can even be applied to flexible applications, said Assoc Prof Yong.
Other team members of the work include Dr Kalon Gopinadhan, Research Fellow at NUSNNI; Professor Thirumalai Venkatesan, Director of NUSNNI; Professor Andre K Geim of the University of Manchester; and Physics Professor Antonio H Castro Neto, Director of CA2DM.
The researchers have filed a patent for the product, with plans to scale up their studies and manufacture industry-size wafers for industrial use.
See press release and media coverage.
Assoc Prof Yang (left) and Prof Venkatesan with the innovative sensor
