PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE PROPERTIES OF A-SI1-XNX-H BASED SUPERLATTICE STRUCTURES

A strong increase in the room temperature photoluminescence efficiency in a-Si1-xNx:H multilayer structures with respect to thick single wel l layers is reported. This result has been correlated to carrier confi nement in the well layers. The multilayer structures consist of a peri odic sequence of barrier (E-04 = 5.0 eV or 4.2 eV) and well layers (E- 04 = 2.1 to 2.6 eV), deposited by plasma enhanced chemical vapor depos ition. Optical properties of these structures show a blue shift of the absorption edge, and evidence that the defect density associated with the internal interfaces is negligible. Electroluminescent devices hav e been obtained by inserting an a-Si1-xNx:H multilayer in a p-i-n stru cture. Such devices show a broad electroluminescence peak, in the yell ow region of the visible spectrum, at about 2.1 eV. (C) 1998 Elsevier Science B.V. All rights reserved.