OPTICAL AND ELECTRICAL-PROPERTIES OF A-SI3N4-H/A-SI-H SUPERLATTICES PREPARED BY PLASMA-ENHANCED NITRIDATION TECHNIQUE

The optical absorption, conductivity and photoluminescence of multilayers consisting of plasma deposited a-Si:H wells and ultra-thin (5 or 7 angstrom) a-Si3N4:H barriers formed by the plasma nitridation of a-Si:H have been investigated. A blue shift of the optical absorption edge and a reduction of the conductivity with a decrease of a-Si:H well width are consistent with a quantum confinement model. The lowering of the luminescence intensity for the multilayers with 5 angstrom thick a-Si3N4:H barriers is interpreted in terms of the miniband formation due to the tunneling broadening of the quantized levels.