The effects of low pressure helium ion bombardment on hydrogenated amorphous silicon

dc.contributor.advisor Vikram L. Dalal
dc.contributor.advisor Gary Tuttle
dc.contributor.advisor Mani Mina
dc.contributor.author Beckman, Michael
dc.contributor.department Electrical and Computer Engineering
dc.date 2018-08-23T08:20:39.000
dc.date.accessioned 2020-06-30T07:40:36Z
dc.date.available 2020-06-30T07:40:36Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 2008
dc.date.issued 2008-01-01
dc.description.abstract <p>The benefits of low pressure Plasma Enhanced Chemical Vapor Deposition (PECVD) using helium as the dilutant gas were investigated in a variety of conditions to identify the techniques feasibility as a low band gap material yielding deposition method. Films and photovoltaic devices with intrinsic layers processed at lower pressures with helium dilution are thought to possess improved characteristics with lower hydrogen content and lowered optical band gaps. When films are grown at lower pressures in the presence of helium the optical band gap tends to decrease. Amorphous silicon a-Si:H generally has a band gap around 1.75eV. This work intends to decrease this band gap as far as possible.;Films grown under these conditions exhibited reasonable growth rates considering the conditions and yielded very good photo and dark conductivity. It was expected that dilution with helium at low pressure would decrease hydrogen content by increasing ion bombardment. This was confirmed by FTIR results that indicated hydrogen content of 7-9%. Both films and devices were fabricated that achieved optical band gaps around 1.62-1.65eV. Devices exhibited Urbach energies that were typically lower than 50meV indicating a good quality amorphous structure.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/14941/
dc.identifier.articleid 15940
dc.identifier.contextkey 7008139
dc.identifier.doi https://doi.org/10.31274/rtd-180813-16083
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/14941
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/68521
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/14941/1453075.PDF|||Fri Jan 14 20:29:02 UTC 2022
dc.subject.disciplines Electrical and Electronics
dc.subject.keywords Electrical and computer engineering;Electrical engineering
dc.title The effects of low pressure helium ion bombardment on hydrogenated amorphous silicon
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication a75a044c-d11e-44cd-af4f-dab1d83339ff
thesis.degree.level thesis
thesis.degree.name Master of Science
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