Abstract

At room temperature, porous Si (PS) exhibits a very strong visible photoluminescence (LP) signal that has potential in opto-electronic applications. While PS is readily fabricated by anodizing crystalline Si (c-Si) in a solution of HF acid, the resulting PL signatures from different samples are found to be dependent on the etching parameters employed and the doping of the Si wafers used. Different theories of the mechanism responsible for the observed PL have been advanced. For example, one theory suggests that the high porosity Si formed in the anodization process can be viewed as a network of nanometer-size crystalline wires and that quantum confinement effects in these one dimensional structures are responsible for widening the band gap of c-Si.¹ Other theories attribute the luminescence to contributions of amorphous Si (a-SiH)² and / or siloxene,³ both of which exhibit PL signatures similar to that of PS.

© 1993 Optical Society of America