Electron emission from deep traps in hydrogenated amorphous silicon and silicon-germanium: Meyer-Neldel behavior and ionization entropy

Qi Long, Steluta Dinca, Eric A. Schiff, Baojie Yan, Jeff Yang, Subhendu Guha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have measured electron drift in amorphous silicon-germanium nip photodiodes using the photocarrier time-of-flight technique. The samples show electron deep-trapping shortly after photogeneration, which is generally attributed to capture by a neutral dangling bond (D 0) to form a negatively charged center (D -). An unusual feature is that electron re-emission from the trap is also clearly seen in the transients. Temperature-dependent measurements on the emission yield an activation energy of about 0.8 eV and the remarkably large value of 10 15 Hz for the emission prefactor frequency. We also compiled results on electron emission from deep traps in a-Si:H, a-SiGe:H, and a-SiC:H from six previous publications. Collectively, these measurements exhibit "Meyer Neldel" behavior for electron emission over a range of activation energies from 0.2-0.8 eV and a prefactor range extending over nine decades, from 10 6 to 10 15 Hz. The Meyer-Neldel behavior is consistent with the predictions of the multi-excitation entropy model. We extract a ionization entropy of 20k B from the measurements, which is very large compared to crystal silicon. We discuss this result in terms of a bond charge model.

Original languageEnglish (US)
Title of host publicationAmorphous and Polycrystalline Thin-Film Silicon Science and Technology - 2011
Pages329-334
Number of pages6
DOIs
StatePublished - Jan 1 2012
Event2011 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 25 2011Apr 29 2011

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1321
ISSN (Print)0272-9172

Other

Other2011 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/25/114/29/11

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'Electron emission from deep traps in hydrogenated amorphous silicon and silicon-germanium: Meyer-Neldel behavior and ionization entropy'. Together they form a unique fingerprint.

Cite this