The single photonic quantum well （PQW） structures are successfully fabricated on ptype silicon wafer by electro chemical etching process, and are used for DNA detection firstly. The red shift of resonance peak is caused by the changing refractive index of PSi layer, which results from coupling of organic molecules into pores. When the porous silicon （PSi） based single PQW biosensors are immersed in complementary deoxyribonucleic acid （DNA） with differ ent concentrations ranging from 0.625 pM to 10,000 pM, a good linear relationship is observed between the red shift of resonance peak and the complementary DNA concentration. Experimental results show that the detection sensitivity of PSibased single PQW biosensors is 3.04 nm/M with a detection limit of 32 nM for 16base pair DNA oligonu cleotides.
LIU Rong-xiaCHEN Liang-lJangZHANG Hong-yanJIA Zhen-hong
By the electrochemical anodization method,we achieve the single-layer macroporous silicon on the N-type silicon,and prepare gold nanoparticles with sodium citrate reduction method. Through injecting the gold nanoparticles into the porous silicon by immersion,the fluorescence quenching mechanism of porous silicon influenced by gold nanoparticles is analyzed. Then the macroporous silicon deposited with gold nanoparticles is utilized to enhance the fluorescence of rhodamine 6G(R6G). It is found that when the macroporous silicon is deposited with gold nanoparticles for 6 h,the maximum fluorescence enhancement of R6G(about ten times) can be realized. The N-type porous silicon deposited with gold nanoparticles can be an excellent substrate for fluorescence detection.
