Enhancing nanocrystallite si electroluminescence by suppressing oxygen decomposition in high-temperature and low-plasma-power PECVD

Abstract

This work demonstrates enhanced electroluminescence and quantum efficiency of a metal-SiOx-Si light-emitting diode (MOSLED) fabricated on nanocrystallite Si (nc-Si)-embedded SiOx plasma-enhanced chemical vapor deposition (PECVD) grown at high substrate temperature and threshold plasma power. Electron energy loss spectroscopy indicates that the energy loss of the primary electron transmitted throughout Si-rich SiOx is reduced from 110 to 106 eV due to the formation of nc-Si. At low plasma power condition, the required dissociation energy of a N2O molecule exceeds that of a SiH4 molecule, while increasing the deposition temperature during PECVD growth facilitates the out-diffusion of adsorbed oxygen atoms. Such enhanced deposition of Si-rich SiOx with excess Si atoms and dense nc-Si after annealing is observed. As the deposition temperature for the Si-rich SiOx increases from 300 to 400 degrees C, the electroluminescent power and quantum efficiency of the nc-Si-based MOSLED are both improved by more than 1 order of magnitude. The output power, turn-on voltage, and internal and external quantum efficiency of the indium tin oxide/SiOx:nc-Si/p-Si/Al diode that was prepared at a substrate temperature of 400 degrees C are 47 nW at 54 mu A, 54.5 V, 5x10(-4), and 1.6x10(-5), respectively. (c) 2007 The Electrochemical Society.