Luminescence from hydrogenated amorphous silicon treated in microwave hydrogen plasma, KOH solution, and oxygen atmosphere

Hydrogenated amorphous silicon (a-Si:H) was prepared by low power plasma-en hanced chemical vapor deposition on Dow coming 7059 glass plates at 100-300 degrees C. The a-Si:H films were treated in a solution of 2.55 KOH:97.5% H 2O at 70 degrees C, oxygen atmosphere, and microwave hydrogen plasma. The i ntensity of photoluminescence for the a-Si:H films by the 488 nm excitation increased by removing a surface layer of about 60 nm in KOH solution, and that for the a-Si:H films treated in oxygen atmosphere was below the detect ion limit. The two treatments did not show remarkable peak shifts on the ph otoluminescence spectrum. However, the microwave hydrogen plasma irradiatio n to the a-Si:H films showed the visible-shift of the peak wavelength of ph otoluminescence with a large increase in emission intensity. (C) 1999 Elsev ier Science S.A. All rights reserved.