The Concentration of (SiH2)n Sites in Low and High Defect Density a-Si:H

The concentration of polysilane chains (SiH 2 ) n , where n ≥ 1, is estimated for higher quality hydrogenated amorphous silicon (a-Si:H) by pulsed proton nuclear magnetic resonance techniques ( 1 H NMR). Our measurements indicate the minimum hydrogen content of approximately 10% of the total hydrogen is in the (SiH 2 ) n configuration. Similar measurements in a high defect density sample (10 17 silicon dangling bond defects cm -3 ) show that (SiH 2 ) n sites account for ~ 15% of the total hydrogen. While the (SiH 2 ) n infrared absorption (IR) modes are observed in the highly defective sample, no such modes are seen in the higher quality material. The results indicate that a significant amount of the total hydrogen content exists as (SiH 2 ) n regardless of film quality.