On-chip ATR sensor (λ = 3.4 μm) based on InAsSbP/InAs double heterostructure for the determination of ethanol concentration in aqueous solutions

Abstract

We discuss photoelectrical properties of an on-chip attenuated total reflection (ATR) sensor for the ethanol concentration measurements in an aqueous solution. The on-chip sensor/microchip was made from a p-InAsSbP/n-InAs monolithic double heterostructure with three mesas/individual diodes grown on a single n+-InAs substrate/waveguide. Two heterostructure diodes were used as photodiodes, while the third one - as a LED. The ethanol concentration was measured via an algorithm based on analysis of the I-V characteristic parameters of a photodiode and the L-I characteristics of the LED. Keywords: photodiodes in the mid-IR range, LEDs in the mid-IR range, on-chip sensor, optical sensors, ATR sensor.