Fabrication of high quality, low bandgap amorphous Silicon & amorphous Silicon Germanium alloy solar cell by Chemical Annealing

dc.contributor.advisor Vikram Dalal
dc.contributor.author Shyam, Ashutosh
dc.contributor.department Electrical and Computer Engineering
dc.date 2018-08-11T17:41:31.000
dc.date.accessioned 2020-06-30T02:27:25Z
dc.date.available 2020-06-30T02:27:25Z
dc.date.copyright Sat Jan 01 00:00:00 UTC 2011
dc.date.embargo 2013-06-05
dc.date.issued 2011-01-01
dc.description.abstract <p>Amorphous Silicon (a-Si:H) has been extensively used as a solar cell material because of its low cost and ease of fabrication. However, the material suffers from generally poorer quality and increase in defect states in response to illumination (Staebler-Wronski effect). For best devices, one also needs to control the bandgap of the material, which depends strongly upon localized Si-H bonding. Although many techniques have been developed to fabricate lower bandgap materials in a-Si:H, most of them lead to the lowering of bandgap at the expense of device /film quality. In this research, we pursue Chemical Annealing (or layer-by-layer growth followed by controlled Ar ion bombardment) as a technique which for fabricating low bandgap, amorphous Silicon materials and devices without adversely affecting the quality of the material. We explore the growth and properties of both a-Si:H and its alloy, a-(Si,Ge):H using chemical annealing.</p> <p>In this work, chemical annealed (CA) and non chemical annealed (NON CA) A-Si:H and A-(Si,Ge):H devices were fabricated at VHF (48MHz) which leads to lower ion damage by Ar. Systematic experiments were carried out to produce high quality devices to study the role of chemical annealing in lowering the bandgap of the solar cells. Films were also fabricated to study electronic properties for various annealing conditions and also to highlight the relationship between hydrogen content and bandgap. Detailed measurements of fundamental properties of the materials and devices were made under various chemical annealing conditions. We also performed light soaking experiments to study the photo-induced instability of normal and chemically annealed devices. The results indicate that the stability of chemical annealed samples is better than continuously grown samples. All the studies convincingly prove that chemical annealing helps reduce the bandgap without adversely affecting material properties.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/10290/
dc.identifier.articleid 1205
dc.identifier.contextkey 2736302
dc.identifier.doi https://doi.org/10.31274/etd-180810-942
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/10290
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/24507
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/10290/Shyam_iastate_0097E_12274.pdf|||Fri Jan 14 18:17:39 UTC 2022
dc.subject.disciplines Electrical and Computer Engineering
dc.subject.keywords amorphous
dc.subject.keywords annealing
dc.subject.keywords germanium
dc.subject.keywords silicon
dc.title Fabrication of high quality, low bandgap amorphous Silicon & amorphous Silicon Germanium alloy solar cell by Chemical Annealing
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication a75a044c-d11e-44cd-af4f-dab1d83339ff
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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