TY  - JOUR
A1  - Guo, Yuanyuan
A1  - Seki, Kosuke
A1  - Miyamoto, Ko-ichiro
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Novel photoexcitation method for light-addressable potentiometric sensor with higher spatial resolution
JF  - Applied physics express : APEX
N2  - A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) is proposed to achieve a higher spatial resolution of chemical images. The proposed method employs a combined light source that consists of a modulated light probe, which generates the alternating photocurrent signal, and a ring of constant illumination surrounding it. The constant illumination generates a sheath of carriers with increased concentration which suppresses the spread of photocarriers by enhanced recombination. A device simulation was carried out to verify the effect of constant illumination on the spatial resolution, which demonstrated that a higher spatial resolution can be obtained.
Y1  - 2014
U6  - http://dx.doi.org/10.7567/APEX.7.067301
SN  - 1882-0786 (E-Journa); 1882-0778 (Print)
VL  - 7
IS  - 6
SP  - 067301-4
PB  - IOP
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Guo, Yuanyuan
A1  - Seki, Kosuke
A1  - Miyamoto, Ko-ichiro
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Device simulation of the light-addressable potentiometric sensor with a novel photoexcitation method for a higher spatial resolution
JF  - Procedia Engineering
N2  - A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) realized a higher spatial resolution of chemical imaging. In this method, a modulated light probe, which generates the alternating photocurrent signal, is surrounded by a ring of constant light, which suppresses the lateral diffusion of photocarriers by enhancing recombination. A device simulation verified that a higher spatial resolution could be obtained by adjusting the gap between the modulated and constant light. It was also found that a higher intensity and a longer wavelength of constant light was more effective. However, there exists a tradeoff between the spatial resolution and the amplitude of the photocurrent, and thus, the signal-to-noise ratio. A tilted incidence of constant light was applied, which could achieve even higher resolution with a smaller loss of photocurrent.
KW  - Light-addressable Potentiometric Sensor
KW  - novel photoexcitation method
KW  - tilted constant illumination
KW  - spatial resolution
Y1  - 2014
U6  - http://dx.doi.org/10.1016/j.proeng.2014.11.369
SN  - 1877-7058
N1  - EUROSENSORS 2014 ; European Conference on Solid-State Transducers <28, 2014>
VL  - 87
SP  - 456
EP  - 459
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Miyamoto, Koichiro
A1  - Seki, Kosuke
A1  - Suto, Takeyuki
A1  - Werner, Frederik
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers
JF  - Sensor and Actuators B: Chemical
N2  - The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.
Y1  - 2018
U6  - http://dx.doi.org/10.1016/j.snb.2018.07.016
SN  - 0925-4005
VL  - 273
SP  - 1328
EP  - 1333
PB  - Elsevier
CY  - Amsterdam
ER  -