Diffusion, drift, and recombination of holes in a-Si:H

R. Schwarz, F. Wang, S. Grebner, Q. Gu, E. A. Schiff

Research output: Contribution to journalConference Articlepeer-review

2 Scopus citations


We compare measurements in a-Si:H of ambipolar diffusion length Lamb (from steady-state photocarrier gratings (SSPG)) and hole drift χ(t) (from time-of-flight (TOF)). Using the response time tR from small-signal photocurrent decay measurements, we find that the equation Lamb2 = 2(kT/e)χ(tR)/E is consistent with the measurements, where E is the electric field inducing hole drift in TOF. Several samples under different temperature and light intensity levels have been studied. This equation has several implications. Under the usual SSPG illumination conditions, electron-hole recombination occurs while holes are still occupying valence bandtail states; hence SSPG is not sensitive to hole capture by deep levels. Furthermore, the experiments show that the Einstein relation is valid for holes in a-Si:H. We are unaware of prior direct tests of this relation in an amorphous semiconductor.

Original languageEnglish (US)
Pages (from-to)427-436
Number of pages10
JournalMaterials Research Society Symposium - Proceedings
StatePublished - 1995
Externally publishedYes
EventProceedings of the 1995 MRS Spring Meeting - San Francisco, CA, USA
Duration: Apr 18 1995Apr 21 1995

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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