Thermally induced photoluminescence quenching centre in hydrogenated amorphous silicon oxynitride

The effect of thermal annealing on the photoluminescence around 2.2-2.9 eV in hydrogenated amorphous silicon oxynitride films was investigated. The lu minescence intensity increases monotonically with an increase in the anneal ing temperature for the samples with lower nitrogen contents (N/O = 0.06, 0 .10 and 0.12). It shows a similar increase up to 500 degreesC, while it dec reases abruptly above 500 degreesC for the samples with higher nitrogen con tents (N/O = 0.14 and 0.18). The density of silicon dangling bonds depends on the annealing temperature in a manner opposite to that of the luminescen ce intensity in all the temperature region. Based on this correlation, it i s thought that the silicon dangling bonds act as the quenching Centre. Infr ared absorption spectroscopy indicated that the precursor of silicon dangli ng bonds was the Si-H bond. Hydrogen was released at temperatures above 500 degreesC from Si-H bonds, resulting in a large number of silicon dangling bonds that quench the luminescence.