Carrier confinement in a-Si1-xNx:H multilayer structures for increased light emission

The increase of room temperature photoluminescence (PL) efficiency of a-Si1-xNx:H/ a-Si3N4:H multilayer structures with respect to thick single well layers is reported to be more than one order of magnitude. An increasing PL efficiency with increasing barrier height and width is also detected. These results have been correlated to carrier confinement into the well layers. The multilayer structures consisting of a periodic sequence of barrier (E04 = 5.0 eV or 4.2 eV) and well layers (E04 = 2.6 eV) have been deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD), with varying well layer thickness and barrier layer thickness. Light emitting devices have been obtained by inserting a multilayer structure as electroluminescent layer in a p-i-n diode, with a-Si1-xCx:H doped layers. Such devices show a visible yellow electroluminescence.