A light-induced increase in the dark conductivity is observed in composite thin films consisting of hydrogenated amorphous silicon (a-Si:H) containing nanocrystalline germanium (nc-Ge) inclusions, synthesized by co-deposition in a dual-chamber plasma enhanced chemical vapor deposition system. Unlike the Staebler-Wronski effect or persistent photoconductivity observed in amorphous semiconductors, this photo-induced excess conductivity is observed even in composite nc-Ge/a-Si:H films with a minimal photosensitivity. The decay of the excess conductivity follows a single-exponential time dependence, with a temperature independent time constant. We propose that spatial separation of photo-excited charge carriers by the compositional morphology present in the film, with tunneling of photo-excited holes into the germanium nanocrystalline inclusions, is involved in the creation and removal of this effect.
Nangoi, J. K., et al. "Photo-induced enhancement of the dark conductivity in nanocrystalline germanium/amorphous silicon composite thin films." Journal of Applied Physics, vol. 124, no. 16, Oct. 2018. https://doi.org/10.1063/1.5031434
Nangoi, J. K., Bodurtha, K., & Kakalios, J. (2018). Photo-induced enhancement of the dark conductivity in nanocrystalline germanium/amorphous silicon composite thin films. Journal of Applied Physics, 124(16). https://doi.org/10.1063/1.5031434
Nangoi, J. K., Bodurtha, K., and Kakalios, J., "Photo-induced enhancement of the dark conductivity in nanocrystalline germanium/amorphous silicon composite thin films," Journal of Applied Physics 124, no. 16 (2018), https://doi.org/10.1063/1.5031434
@article{osti_1478134,
author = {Nangoi, J. K. and Bodurtha, K. and Kakalios, J.},
title = {Photo-induced enhancement of the dark conductivity in nanocrystalline germanium/amorphous silicon composite thin films},
annote = {A light-induced increase in the dark conductivity is observed in composite thin films consisting of hydrogenated amorphous silicon (a-Si:H) containing nanocrystalline germanium (nc-Ge) inclusions, synthesized by co-deposition in a dual-chamber plasma enhanced chemical vapor deposition system. Unlike the Staebler-Wronski effect or persistent photoconductivity observed in amorphous semiconductors, this photo-induced excess conductivity is observed even in composite nc-Ge/a-Si:H films with a minimal photosensitivity. The decay of the excess conductivity follows a single-exponential time dependence, with a temperature independent time constant. We propose that spatial separation of photo-excited charge carriers by the compositional morphology present in the film, with tunneling of photo-excited holes into the germanium nanocrystalline inclusions, is involved in the creation and removal of this effect.},
doi = {10.1063/1.5031434},
url = {https://www.osti.gov/biblio/1478134},
journal = {Journal of Applied Physics},
issn = {ISSN 0021-8979},
number = {16},
volume = {124},
place = {United States},
publisher = {American Institute of Physics},
year = {2018},
month = {10}}