Enhancement of non-geminate electron–hole pair recombination induced by strong electric field in hydrogenated amorphous silicon (a-Si:H): effective-temperature concept

Abstract

Experimental evidence for field-induced enhancement of non-geminate, i.e. distant-pair (DP), recombination and shortening of the DP lifetime, τ _D, by almost two orders of magnitude, is given for undoped hydrogenated amorphous silicon (a-Si:H) subjected to a strong electric field, F, up to 100 kV cm⁻¹ at a temperature T = 3.7 K. The interplay between the T- and F-dependences of the lifetime τ _D is interpreted on the basis of the effective-temperature theory developed for the high-field hopping transport of charge carriers in disordered materials at low T. The results indicate that the DP recombination event is closely connected to transport phenomena in a-Si:H.

Acknowledgements

The authors thank S. Kobayashi of TPU for preparing the samples. The work was financially supported in part by the Japan Private School Promotion Foundation. The authors also acknowledge Professor S. Kasap, University of Saskatchewan, Canada for his critical reading of the manuscript.