Fermi-Level Dependence of the Charge State of Diffusing Hydrogen in Amorphous Silicon

Howard M. Branz, Robert Reedy, Richard S. Crandall, Harv Mahan, Yueqin Xu, Brent P. Nelson

Research output: Contribution to journalArticlepeer-review

16 Scopus Citations


We observe that the charge state of diffusing hydrogen depends upon the electronic Fermi level (Ef) in hydrogenated amorphous silicon (a-Si:H). We incorporate a thin layer of deuterium (2H) at various positions between the n- and p-layers of i-n-i-p-i structures on crystalline silicon substrates. The electric field (F) is above 6 × 104 V/cm at each 2H layer. After annealing, marked asymmetries in the secondary ion mass spectrometry profiles of diffused deuterium are observed. With the 2H layer placed near the p-layer (Ef near the valence band), diffusion is into the p-layer, indicating H+ moving with F. With the 2H layer near the n-layer (Ef near the conduction band), most diffusion is into the n-layer, indicating H- moving against F. Because the Si-H bond is neutral, the charged diffusing species must be emitted mobile H. We estimate an effective correlation energy of 0.4 ± 0.1 eV for the mobile H.

Original languageAmerican English
Pages (from-to)191-195
Number of pages5
JournalJournal of Non-Crystalline Solids
Issue numberPART 1
StatePublished - 2002

NREL Publication Number

  • NREL/JA-520-32891


Dive into the research topics of 'Fermi-Level Dependence of the Charge State of Diffusing Hydrogen in Amorphous Silicon'. Together they form a unique fingerprint.

Cite this