Photoluminescence of amorphous multilayer structures a-C:H/a-Si:H

The optical absorption edge and the photoluminescence spectra of amorphous hydrogenated diamond-like carbon (a-C:H) films are investigated in the temperature range 4.2-900 K. Low-dimensional multilayer structures a-C:H/a-Si:H, in which a-C:H with an optical band gap E-g = 4.5 eV is used as a barrier, are prepared for the first time. It is found that amorphous hydrogenated silicon (a-Si:H) films with a thickness d < 100 angstrom exhibit quantum-confinement effects. Analysis of the photoluminescence spectra and the optical absorption edge of the a-Si:H films shows that the structures a-C:H/a-Si:H have a sharp interface and that charge carriers in the a-Si:H film undergo quantization.