Abstract

We have constructed and characterized visible electroluminescent devices based on Si nanocrystallite thin films. The key to stable electroluminescent emission is the nature of the Si surface capping layer, which determines the efficiency and stability of the devices. The layers must be transparent to the emitted light, provide sufficient electrical contact to insure carrier transport to the active layer, stabilize the Si surfaces to prevent chemical and electrical degradation, and passivate the dangling surface bonds which would act as non-radiative recombination centers and quench emission. Our devices use Al and ITO (indium tin oxide) electrodes, as well as transparent polymer capping layers to provide the necessary carrier injection and chemical and electronic passivation for the silicon nanocrystallite active layer. Their electrical and optical behavior was evaluated in terms of the I-V characteristics, electroluminescence spectra, and photoluminescence spectra. These devices represent a first step towards developing efficient silicon based light-emitting technology.

© 1995 Optical Society of America