title: Electron beam induced current in the high injection regime.
abstract: Electron beam induced current (EBIC) is a powerful technique which measures the charge collection efficiency of photovoltaics with sub-micron spatial resolution. The exciting electron beam results in a high generation rate density of electron-hole pairs, which may drive the system into nonlinear regimes. An analytic model is presented which describes the EBIC response when the total electron-hole pair generation rate exceeds the rate at which carriers are extracted by the photovoltaic cell, and charge accumulation and screening occur. The model provides a simple estimate of the onset of the high injection regime in terms of the material resistivity and thickness, and provides a straightforward way to predict the EBIC lineshape in the high injection regime. The model is verified by comparing its predictions to numerical simulations in one- and two-dimensions. Features of the experimental data, such as the magnitude and position of maximum collection efficiency versus electron beam current, are consistent with the three-dimensional model.
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Haney
authors.forename: Heayoung P
authors.initials: HP
authors.lastname: Yoon
authors.forename: Prakash
authors.initials: P
authors.lastname: Koirala
authors.forename: Robert W
authors.initials: RW
authors.lastname: Collins
authors.forename: Nikolai B
authors.initials: NB
authors.lastname: Zhitenev