Fabrication of Gas Sensor Device for H2 and NO2 from Porous Silicon

Abstract

A nanocrystalline porous silicon (PS) layer was prepared by electrochemical etching method of p-type silicon wafer in hydrofluoric acid (HF). The properties of porous silicon structure under various etching times (10-50 min), HF concentrations, and current density were studied. The study included photoluminescence (PL), morphology, x-ray, and gas sensor. The results (PL) spectra (peak wavelength) can be shifted from (505 to 625) nm. PL analysis indicated that the energy band gap can be tuned from (1.984-2.455) eV with respect to etched time. Atomic Force Microscopy (AFM) analysis showed that the PS layer had a sponge-like structure. Surface roughness and the pyramid-like hillocks on the entire surface play an important role in variation visible luminescence. The AFM images shows that the average diameter of the PS layer pore and thickness the Silicon decreased when etching time increase and the average diameter particleboard ranged from (80.8-35.4) nm. PS X-ray topography studies that the skeleton maintained its silicon crystalline structure after anodization. PS Sensors were fabricated and tested successfully on H 2 and No 2 gas.

Room temperature NO2 gas sensor based on stain-etched porous silicon: Towards a low-cost gas sensor integrated on silicon

“…Chemical functionalization of the porous silicon surface shows the potential for developing a variety of gas sensors [6]. Recently, PS gas sensor has been investigated especially for NO2 detection [9,10]. Although PS sensors show good sensitivity when exposed to NO2, some problems such as selectivity, repeatability, response-recovery characteristics and long-term stability need to be considered.…”

Study of the Vacuum Pressure Sensing from the Electrical Resistance Response of Porous Silicon Fabricated via Photo-Electrochemical Technique

“…In addition, it is also easy to manufacture with the advantage of controlling surface morphology by adjusting configuration variables, including current density, electrolyte composition, temperature, etching time, and Si crystal resistance [15,16]. The electrical and optical response of PSi -based sensor was investigated by making measurements of photoluminescence [17], sensitivity, and temporal response [18][19][20]. Kang-san Kim and Gwiy-san Chung [4], investigated this by sensing the hydrogen properties of Pd on the PSi carbide, and it showed an increase in response and resistance ratio, which contributed to the consideration of PSi -based sensors being feasible for use in solid-state gas sensors and designed for operation in harsh environmental conditions.…”