Electrical Properties of Porous Silicon for N2 Gas Sensor

Abstract

The application of porous silicon (PSi) for gas sensing devices has gained a considerable attention in the last decade. This work considers the electrical features of PSi layers prepared by electrochemical etching. We find that in order to get a better understanding of the absorption properties of PSi surface, it is necessary to know how the PSi morphology depends on the etching parameters. The physical structure of PSi, i.e., porosity, and pore size distribution can be controlled by changing the Hydrofluoric Acid concentration, current density, anodizing length and etching time in anodizing procedure. We describe our test system for gas sensors and investigate on the electrical behavior of PSi layers (p-type) in N2 gas for various fabrication conditions. The results show that the current density increases significantly as N2 gas is adsorbed. The measurements of the I-V characteristics were carried out at atmospheric pressure, room temperature, and with N2 gas as well.