Modeling of the electron beam induced current signal in nanowires with an axial p-n junction

Abderrezak Lahreche; Andrey V Babichev; Yamina Beggah; Maria Tchernycheva

doi:10.1088/1361-6528/ac7887

Modeling of the electron beam induced current signal in nanowires with an axial p-n junction

Nanotechnology. 2022 Jul 4;33(39). doi: 10.1088/1361-6528/ac7887.

Authors

Abderrezak Lahreche^{1

2}, Andrey V Babichev^{3

4}, Yamina Beggah², Maria Tchernycheva⁵

Affiliations

¹ Department de technologie, Université A.Mira de Bejaia, 6000 Bejaia, Algérie.
² Laboratoire Matériaux: Elaborations-Propriétés - Applications (LMEPA), Université Jijel, 18000 Jijel, Algérie.
³ Saint Petersburg Electrotechnical University "LETI", 197376 St. Petersburg, Russia.
⁴ ITMO University, 197101 St. Petersburg, Russia.
⁵ Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, University Paris-Saclay, F-91120 Palaiseau, France.

PMID: 35700698
DOI: 10.1088/1361-6528/ac7887

Abstract

A tridimensional mathematical model to calculate the electron beam induced current (EBIC) of an axial p-n nanowire junction is proposed. The effect of the electron beam and junction parameters on the distribution of charge carriers and on the collected EBIC current is reported. We demonstrate that the diffusion of charge carriers within the wire is strongly influenced by the electrical state of its lateral surface which is characterized by a parameter called surface recombination velocity (v_r). When the surface recombination is weak (i.e. lowv_rvalue), the diffusion of charge carriers occurs in one dimension (1D) along the wire axis, and, in this case, the use of bulk EBIC models to extract the diffusion length (L) of charge carriers is justified. However, when the surface effects are strong (i.e. highv_rvalues), the diffusion happens in three dimensions (3D). In this case, the EBIC profiles depend onv_rvalue and two distinct cases can be defined. If theLis larger than the nanowire radius (r_a), the EBIC profiles show a strong dependency with this parameter. This gives evidence that the recombination of generated carriers on the surface throughv_ris the dominant process. In this situation, a decrease of two orders of magnitude in the EBIC profiles computed with a high and a lowv_rvalue is observed in neutral regions of the junction. For the case ofLsmaller thanr_athe dependency of the EBIC profiles on thev_ris weak, and the prevalent recombination mechanism is the bulk recombination process.

Keywords: axial nanowire p-n junction; diffusion length; electrical nanoscale characterization; electron beam induced current microscopy; modelling; surface recombination.