Structural, Optical, and Photovoltaic Properties of Tetracene Thin Films

Authors

  • M. P. Gorishnyi Institute of Physics, Nat. Acad. of Sci. of Ukraine
  • A. B. Verbitsky Institute of Physics, Nat. Acad. of Sci. of Ukraine

DOI:

https://doi.org/10.15407/ujpe61.01.0050

Keywords:

tetracene thin films, Al–Tc–Au heterostructures, photovoltaic response

Abstract

The structure, absorption spectra, and photovoltaic response of tetracene (Tc) thin films 120 and 200 nm in thickness deposited in a vacuum of 6.5 MPa onto different substrates at room temperature have been studied. The photovoltaic response is measured by the method of capacitor cell. It is found that island films are formed on glass and quartz substrates, whereas solid polycrystalline films on copper ones, which is a result of the different interaction energies of Tc molecules with one another and with substrate molecules, molecules of ITO layers, and carbon atoms on the substrate surface. In quasi-amorphous films at a temperature of 4.2 K, excited molecules are deformed stronger as compared to those in polycrystalline films and free molecules at 300 K.
The photo-emf Vf at the front (illuminated) free surfaces of Tc films is negative in the spectral interval of 1.637–3.258 eV, which testifies to the hole photoconductivity in the films. The photo-emf Vr at the rear surface of 120-nm Tc films (illumination through the ITO electrode, which directly contacted with the Tc film) changed its sign in the spectral intervals of 2.193–2.494 and 2.927–3.153 eV as the oxygen concentration in the measuring cell decreased, which testifies to a change of the energy band bending in the Tc films near their rear and front (free) surfaces.

Published

2019-01-08

How to Cite

Gorishnyi, M. P., & Verbitsky, A. B. (2019). Structural, Optical, and Photovoltaic Properties of Tetracene Thin Films. Ukrainian Journal of Physics, 61(1), 50. https://doi.org/10.15407/ujpe61.01.0050

Issue

Section

Solid matter