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Proceedings Paper

Investigation of ultrahigh sensitivity in GaInAsP nanolaser biosensor
Author(s): Yoshito Saijo; Takumi Watanabe; Yu Hasegawa; Yoshiaki Nishijima; Toshihiko Baba
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Paper Abstract

We have developed GaInAsP semiconductor photonic crystal nanolaser biosensor and demonstrated the detection of ultralow-concentration (fM to aM) proteins and deoxyribonucleic acids (DNAs) adsorbed on the device surface. In general, this type of photonic sensors exploiting optical resonance has been considered to detect the refractive index of biomolecules via the wavelength shift. However, this principle cannot explain the detection of such ultralowconcentration. Therefore, we investigated another candidate principle, i.e., ion sensitivity. We consider such a process that 1) the electric charge of biomolecules changes the nanolaser’s surface charge, 2) the Schottky barrier near the semiconductor surface is increased or decreased, 3) the distribution of photopumped carriers is modified by the barrier, 4) the refractive index of the semiconductor is changed by the carrier effects, and 5) the laser wavelength shifts. To confirm this process, we electrochemically measured the zeta and flatband potentials when charged electrolyte polymers were adsorbed in water. We clearly observed that these potentials temporally behaved consistently with that of the laser wavelength, which suggests that polymers significantly acted on the Schottky barrier. The same behaviors were also observed for the adsorption of 1 fM DNA. We consider that a limited number of charged DNA changed the surface functional group of the entire device surface. Such charge effects will be the key that achieves the ultrahigh sensitivity in the nanolaser biosensor.

Paper Details

Date Published: 20 February 2018
PDF: 7 pages
Proc. SPIE 10510, Frontiers in Biological Detection: From Nanosensors to Systems X, 105100C (20 February 2018);
Show Author Affiliations
Yoshito Saijo, Yokohama National Univ. (Japan)
Takumi Watanabe, Yokohama National Univ. (Japan)
Yu Hasegawa, Yokohama National Univ. (Japan)
Yoshiaki Nishijima, Yokohama National Univ. (Japan)
Toshihiko Baba, Yokohama National Univ. (Japan)

Published in SPIE Proceedings Vol. 10510:
Frontiers in Biological Detection: From Nanosensors to Systems X
Amos Danielli; Benjamin L. Miller; Sharon M. Weiss, Editor(s)

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