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Yi Jing, Samir Damle, Brandon Bosse, Sue Bauchner, William R Freeman, Yu-Hwa Lo; Characterization of the Silicon Nanowire Optoelectronic Device For Subretinal Prosthesis. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4201.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study is to characterize the performance of a silicon nanowire optoelectronic device as artificial retinal photoreceptors.
Silicon nanowire photodiode arrays were fabricated using nanofabrication techniques. The current-voltage characteristics were investigated under dark and illumination using a semiconductor device analyzer. In addition, the spectral photo response of the device over visible and infrared (IR) wavelengths was measured using a solar cell quantum efficiency measurement system. To study the electrical current output of the device, chronoamperometry measurements were performed under IR illumination using a three-electrode configuration with device immersed in phosphate-buffered saline electrolyte.
The Si nanowire photodiode array exhibited high photo responsivities to visible and IR illumination. The peak responsivity of the device occurs at a wavelength of 750 nm. The device used for wet characterization consists of 1512 electrodes. It is optically addressed and can be electrical biased. Under continuous 850 nm IR illumination and pulsed bias, the responsivity of the device was measured to be 1.7 A/W at 0.5 V bias and 2.1 A/W at 1.5V bias, respectively. This constitutes a fivefold improvement in responsivity compared to conventional unbiased micro-photodiode array for retinal prosthesis. At 10ms pulse, each electrode was able to inject 1-5nC charges per phase under a bias of 0.5 to 1.5 V and IR illumination of 50-200 μW/mm2.
We demonstrated a high-responsivity silicon nanowire based optoelectronic device for retinal prosthesis application. The charge injected by a single electrode of the device is well above the threshold for subretinal electrical stimulation of retina reported in literature.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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