Microstructure Dependent Opto-Electronic Properties of Amorphous Hydrogenated Silicon Thin Films

• Published in: Materials today : proceedings Vol. 5; no. 1; pp. 2527 - 2533
• Main Authors: Shaik, Habibuddin, Sheik, Abdul Sattar, Rachith, S.N., Rao, G. Mohan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2018
• Subjects: a-Si:H; amorphous silicon; continuous random network; hydrogen bonding configuration; hydrogen concentration; photoconductivity; photoconductivity; hydrogen concentration; amorphous silicon; continuous random network; hydrogen bonding configuration; a-Si:H
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2017.11.035

The variation in the formation of amorphous hydrogenated silicon (a-Si:H) network in DC, pulsed DC (PDC) and RF sputtering was studied. The effect of network formation on the photo-electronic properties is investigated along with its applicability to the Continuous Random Network (CRN) model. It was found that DC deposited a-Si:H films obey the CRN model up to a hydrogen concentration (CH) ∼ 10 at.% H and there after it starts deviating. The deviation is more prominent for a-Si:H films deposited by PDC and RF sputtering. Also it was found that, DC sputtering is more suitable to deposit device grade a-Si:H rather than PDC and RF sputtering. Also DC deposited films are found to be of more photoactive compared to PDC and RF films. The domination of dihydrides (Si-H2) over monohydrides (Si-H) start at very low CH values in PDC and RF films, whereas, in DC deposited films it started at CH ∼13 at.% H. DC films are found to be of good quality as hydrogen is dominantly present in Si-H configuration. The effect of CH is considerably more on dark conductivity of a-Si:H films. The variation in band gap and photo conductivity is also investigated.