Photon Emission in CuInSe2 Thin Films Observed by Scanning Tunneling Microscopy

Manuel J. Romero, Chun Sheng Jiang, Rommel Noufi, Mowafak Al-Jassim

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25 Scopus Citations


We report on the observation of photon emission from CuIn Se2 (CIS) thin films by scanning tunneling microscopy (STM), which results from the radiative recombination induced by tunneling electrons. Scanning tunneling luminescence (STL) spectroscopy suggests that photons are emitted near the surface of CIS. STL is excited by recombination of tunneling electrons with available holes in CIS or electron-hole recombination by impact ionization-unipolar and bipolar excitation, respectively. Which process becomes predominant depends on the voltage applied to the STM tip. Under unipolar excitation, the photon intensity decreases on grain boundaries when compared to grain interiors. Under bipolar excitation, on the other hand, no differences are observed in photon intensity. A reduction of the density of holes in grain boundaries, relative to grain interiors, can explain the observed behavior.

Original languageAmerican English
Article number143115
Pages (from-to)1-3
Number of pages3
JournalApplied Physics Letters
Issue number14
StatePublished - 4 Apr 2005

NREL Publication Number

  • NREL/JA-520-35958


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