VISIBLE-LIGHT EMITTING FROM THE SURFACE-LAYER ON A POROUS LAYER

In the present paper, the cathode luminescence (CL) spectrum of visibl e light emitting porous silicon (peak at 680nm) was obtained and prove d to be similar to the photoluminescence one. The CL was studied by sc anning electron microscopy (SEM). The SEM photographs of the surface o f the sample show that the CL only emits from the surface layer and th ere is no CL from the porous layer where the surface layer was moved a way. The SEM photographs of the cross-section of the sample show the s ame result. The above experiments suggest again that the visible lumin escence from the porous silicon is from the fluorescent material produ ced in the surface layer of the porous silicon.