Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal

Handle URI:
http://hdl.handle.net/10754/598238
Title:
Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal
Authors:
Dacuña, Javier; Xie, Wei; Salleo, Alberto
Abstract:
We used a mobility edge transport model and solved the drift-diffusion equation to characterize the space-charge-limited current of a rubrene single-crystal hole-only diode. The current-voltage characteristics suggest that current is injection-limited at high voltage when holes are injected from the bottom contact (reverse bias). In contrast, the low-voltage regime shows that the current is higher when holes are injected from the bottom contact as compared to hole injection from the top contact (forward bias), which does not exhibit injection-limited current in the measured voltage range. This behavior is attributed to an asymmetric distribution of trap states in the semiconductor, specifically, a distribution of traps located near the top contact. Accounting for a localized trap distribution near the contact allows us to reproduce the temperature-dependent current-voltage characteristics in forward and reverse bias simultaneously, i.e., with a single set of model parameters. We estimated that the local trap distribution contains 1.19×1011 cm -2 states and decays as exp(-x/32.3nm) away from the semiconductor-contact interface. The local trap distribution near one contact mainly affects injection from the same contact, hence breaking the symmetry in the charge transport. The model also provides information of the band mobility, energy barrier at the contacts, and bulk trap distribution with their corresponding confidence intervals. © 2012 American Physical Society.
Citation:
Dacuña J, Xie W, Salleo A (2012) Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal. Physical Review B 86. Available: http://dx.doi.org/10.1103/PhysRevB.86.115202.
Publisher:
American Physical Society (APS)
Journal:
Physical Review B
KAUST Grant Number:
KUS-C1-015-21
Issue Date:
6-Sep-2012
DOI:
10.1103/PhysRevB.86.115202
Type:
Article
ISSN:
1098-0121; 1550-235X
Sponsors:
This paper was based on work supported by the Center for Advanced Molecular Photovoltaics (Award No. KUS-C1-015-21), made by King Abdullah University of Science and Technology (KAUST). W. X. is funded by NSF Materials Research Science and Engineering Center at the university of Minnesota under Grant No. DMR-0819885.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorDacuña, Javieren
dc.contributor.authorXie, Weien
dc.contributor.authorSalleo, Albertoen
dc.date.accessioned2016-02-25T13:17:11Zen
dc.date.available2016-02-25T13:17:11Zen
dc.date.issued2012-09-06en
dc.identifier.citationDacuña J, Xie W, Salleo A (2012) Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal. Physical Review B 86. Available: http://dx.doi.org/10.1103/PhysRevB.86.115202.en
dc.identifier.issn1098-0121en
dc.identifier.issn1550-235Xen
dc.identifier.doi10.1103/PhysRevB.86.115202en
dc.identifier.urihttp://hdl.handle.net/10754/598238en
dc.description.abstractWe used a mobility edge transport model and solved the drift-diffusion equation to characterize the space-charge-limited current of a rubrene single-crystal hole-only diode. The current-voltage characteristics suggest that current is injection-limited at high voltage when holes are injected from the bottom contact (reverse bias). In contrast, the low-voltage regime shows that the current is higher when holes are injected from the bottom contact as compared to hole injection from the top contact (forward bias), which does not exhibit injection-limited current in the measured voltage range. This behavior is attributed to an asymmetric distribution of trap states in the semiconductor, specifically, a distribution of traps located near the top contact. Accounting for a localized trap distribution near the contact allows us to reproduce the temperature-dependent current-voltage characteristics in forward and reverse bias simultaneously, i.e., with a single set of model parameters. We estimated that the local trap distribution contains 1.19×1011 cm -2 states and decays as exp(-x/32.3nm) away from the semiconductor-contact interface. The local trap distribution near one contact mainly affects injection from the same contact, hence breaking the symmetry in the charge transport. The model also provides information of the band mobility, energy barrier at the contacts, and bulk trap distribution with their corresponding confidence intervals. © 2012 American Physical Society.en
dc.description.sponsorshipThis paper was based on work supported by the Center for Advanced Molecular Photovoltaics (Award No. KUS-C1-015-21), made by King Abdullah University of Science and Technology (KAUST). W. X. is funded by NSF Materials Research Science and Engineering Center at the university of Minnesota under Grant No. DMR-0819885.en
dc.publisherAmerican Physical Society (APS)en
dc.titleEstimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystalen
dc.typeArticleen
dc.identifier.journalPhysical Review Ben
dc.contributor.institutionStanford University, Palo Alto, United Statesen
dc.contributor.institutionUniversity of Minnesota Twin Cities, Minneapolis, United Statesen
kaust.grant.numberKUS-C1-015-21en
kaust.grant.fundedcenterCenter for Advanced Molecular Photovoltaics (CAMP)en
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