Electroluminescence of silicon nanocrystals in p-i-n diode structures

摘要

A new method of fabrication of nanocrystalline silicon-based light-emitting-devices is introduced. Si nanocrystals are derived from combustion or pyrolysis of silane and etched subsequently in a two-phase solution of HF. The p-i-n diodes have an active layer (20-60 nm) of Si nanocrystals sandwiched between thin isolating layers of SiO_2 or a-Si: H and a top-layer of p doped silicon, the substrate being of n Si. For both types of structures, electroluminescence is observed under forward bias exceeding 5 V and the spectrum consists of a broad band (due to a large size distribution of Si nanocrystals) centred around 650 nm and giving a yellowish appearance when observed by naked-eye. The integrated electroluminescence intensity growths with the square of applied bias.