• Rashidi, Amin
• Mondal, Tanmay
• Laursen, Kjeld
• Corbett, Brian
• Hosseini, Seyedsina
• Moradi, Farshad

Abstract

<p>We present the fabrication, characterization, and demonstration of high-efficiency ultrasound-powered microlight emitting diodes (µLED) for use in optogenetic applications. InGaN based blue-emitting LED material wafers grown on a patterned sapphire substrate (PSS) were used to assist in the out-scattering of the light. The turn-on voltage of the LEDs is around 2.5 volts and the electrical ideality factor is 1.2 confirming high radiative recombination efficiency. A power density of more than 50 mW/mm² was obtained from a 130 × 300 µm² LED with a mesa of 100 µm diameter at 3 mA which is much more than is required to excite channelrhodopsin transfected neural cells. A high external quantum efficiency (EQE) of 33% is obtained at 3 mA measured in an integrating sphere. The peak wavelength of the µLED was measured at 483 nm at different current densities. The µLEDs are integrated directly onto a rectifier and Piezoelectric Transducer (PZT) harvester to realise a highly efficient ultrasound-powered light delivery unit capable to generate mWs of optical power. The concept was validated by powering the integrated device with ultrasound.</p>

Topics

• density
• impedance spectroscopy