Sensing devices to sense trace chemicals and identify chemical compounds: namely (1) security sensing devices, namely: chemical sensors, biochemical weapon sensors, explosives and drug screening sensors, human body gas phase chemical identification sensors; (2) forensic sensing devices, namely drug screening sensors, false signature sensors, false current bills sensors; human identification sensors; DNA/protein identification sensors, blood identification sensors, gun powder identification sensors, false products identification sensors for gemstone, currency bills, trademark, ink, silk, art, paint masterpiece, medicine, pill and liquid, and wine; (3) medical clinic invasive in vivo diagnosis sensing devices, namely breath test sensors for cancer, liver cirrhosis, failing kidney, non-invasive blood test sensors for diabetes and blood coagulation, minimal invasive in vivo diagnosis sensors for Alzheimer's disease, bodily fluid test sensors for drug screening, kidney and ladder disease, non-invasive diagnosis sensors for eye disease, Endoscopes inspection sensors, sensors for "Smart Toilet" used for drug screening and early disease diagnosis, (4) food & beverage sensing devices, namely toxic chemical monitoring sensors for health purposes, Ethylene monitoring sensors for stored fruit and vegetable with longer lifetime application, (5) environmental sensing devices, namely pesticide residue monitoring sensors, pollution investigation sensors; sensor for use in in-line monitoring wet chemical concentration in wet chemical process line, stand-off monitoring of sealed chemical tank, remote trace chemical detection, semiconductor wafer defect evaluation, and production line monitoring and quality control for medicine and wine