Infrared multiphoton-excited luminescence in porous silicon

Summary form only given. We have studied luminescence from porous Si induced by infrared multiphoton excitation (MPE) using a picosecond tunable infrared source. The n-photon carrier excitation process was found to be direct at small n, but indirect through the stretch vibrational resonances of the SiH/sub x/ surface species in porous Si with n=7 or 8.