Amorphous silicon balanced photodiode for microfluidic applications

Domenico Caputo; Giampiero de Cesare; Augusto Nascetti; Riccardo Scipinotti

doi:10.1117/12.2017420

3 May 2013 Amorphous silicon balanced photodiode for microfluidic applications

Domenico Caputo, Giampiero de Cesare, Augusto Nascetti, Riccardo Scipinotti

Proceedings Volume 8774, Optical Sensors 2013; 87740V (2013) https://doi.org/10.1117/12.2017420
Event: SPIE Optics + Optoelectronics, 2013, Prague, Czech Republic

Abstract

In this paper, we present the first integration of an amorphous silicon balanced photosensor with a microfluidic network to perform on-chip detection for biomedical applications, where rejection of large background light intensity is needed. This solution allows to achieve high resolution readout without the need of high dynamic range electronics. The balanced photodiode is constituted by two series-connected a-Si:H/a-SiC:H n-i-p stacked junctions, deposited on a glass substrate. The structure is a three terminal device where two electrodes bias the two diodes in reverse conditions while the third electrode (i.e. the connection point of the two diodes) provides the output signal given by the differential current. The microfluidic network is composed of two channels made in PolyDimetilSiloxane (PDMS) positioned over the glass substrate on the photodiode-side aligning each channel with a diode. This configuration guarantees an optimal optical coupling between luminescence events occurring in the channels and the photosensors. The experiments have been carried out measuring the differential current in identical and different conditions for the two channels. We have found that: the measurement dynamic range can be increased by at least an order of magnitude with respect to conventional photodiodes; the balanced photodiode is able to detect the presence or absence of water in the channel; the presence of fluorescent molecules in the channel can be successful detected by our device without any need of optical filter for the excitation light. These preliminary results demonstrate the successful integration of a microfluidic network with a-Si:H photosensor for on-chip detection in biomedical applications.

Citation Download Citation

Domenico Caputo, Giampiero de Cesare, Augusto Nascetti, and Riccardo Scipinotti "Amorphous silicon balanced photodiode for microfluidic applications", Proc. SPIE 8774, Optical Sensors 2013, 87740V (3 May 2013); https://doi.org/10.1117/12.2017420

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available