Dispersive Transient Photocurrent in Amorphous Silicon at High and Low Trap-State Occupations
Transient photocurrent in hydrogenated amorphous silicon is studied in all relevant time regimes following the illumination of a pulse of light at one end of the sample. When both electron and hole transport are taken into consideration, we find that, at a low occupation level of trap states or at a low intensity of illumination, there are five well-defined current slopes. The first three are located at a short-time range, which has not been probed experimentally, and they are due to the electron transport. The last two slopes originate from the well-known phenomenon of hole transport. Each bend from a current slope change has a particular physical meaning and is interpreted. At a high illumination intensity, all five current slopes become less well-defined, and the two current slopes that are due to hole transport can change drastically because of significant space-charge effects. In particular, one of the hole slopes can even change from negative to positive, and the result is quite different from the well-known dispersive transport theory in disordered semiconductors.
M. H. Chu and C. Wu, "Dispersive Transient Photocurrent in Amorphous Silicon at High and Low Trap-State Occupations," Journal of Physical Chemistry B, vol. 104, no. 16, pp. 3924-3929, American Chemical Society (ACS), Apr 2000.
The definitive version is available at http://dx.doi.org/10.1021/jp993656r
Electrical and Computer Engineering
Keywords and Phrases
Electric space charge; Electron transport properties; Electron traps; Photocurrents, Hole transport; Trap-state occupations, Amorphous silicon
International Standard Serial Number (ISSN)
Article - Journal
© 2000 American Chemical Society (ACS), All rights reserved.