By Will Soutter
Researchers at Purdue University have devised a method to mass produce nanoresonators, a class of devices known as nanoelectromechanical systems (NEMS), which can replace electronic components in devices to improve performance of mobile phones.
Scanning Electron Microscope Image of the Nanoresonator (Credit: Purdue Unievrsity)
Cellular communication is plagued by problems such as slow downloads, poor call quality, busy signals and dropped calls. The reason for this is that the radio spectrum available for mobile communication is not sufficient enough to accommodate each and every handheld device. The telecommunication industry is striving to resolve this problem by developing systems that function in sharply defined frequency channels in order to accommodate more such systems within allocated spectrum. This means that radio devices such as mobile phones require high quality precision filters that eliminate noise and allow the required frequency to pass through. The team from Purdue has used existing technology to create devices that perform this function.
The core of the device developed by the researchers consists of a silicon beam fastened at both the ends and measures 130 nm in width and 2 µm in length. The silicon beam vibrates in response to applied voltage. It can thus be tuned to vibrate vertically or from side-to-side by applying alternating current voltage. The fabrication method employed to prepare these devices is silicon-on-insulator, or SOI. This method is compatible with CMOS manufacturing process adopted for electronic devices and hence facilitates the easy incorporation of these devices in electronic circuits. The performance of no two nanoscale devices is same owing to differences in manufacturing. This necessitates tuning of the devices. The nanoresonators were found to perform better than other resonators in tuning. The nanoresonators can also have other applications in sensors.