Abstract
In this paper, we propose an ultra-low detection limit silicon photonic sensors based on one dimensional microcavity structures with electrochemical signal enhancement for heavy metal ion detection in water. The 1-D microcavity [1] consists of two distributed Bragg reflectors (DBR) symmetrically placed about a defect layer fabricated by successive electrochemical etchings (ECE). It detects Cd 2+ concentration by the characteristic peak shift in the spectrum due to different concentrations of the ions in liquid or refraction index, RI, variation [2], and the detection limit now can approach 1 ppb by the enhancement of electrochemical reduction process, not only 10 5 times more sensitive than before but also with a EC specific selectivity for the target ions simultaneously.