Comparison of Three E-Beam Techniques for Electric Field Imaging and Carrier Diffusion Length Measurement on the Same Nanowires.
Whereas nanowire (NW)-based devices offer numerous advantages compared to bulk ones, their performances are frequently limited by an incomplete understanding of their properties where surface effect should be carefully considered. Here, we demonstrate the ability to spatially map the electric field and determine the exciton diffusion length in NW by using an electron beam as the single excitation source. This approach is performed on numerous single ZnO NW Schottky diodes whose NW radius vary from 42.5 to 175 nm. The dominant impact of the surface on the NW properties is revealed through the comparison of three different physical quantities recorded on the same NW: electron-beam induced current, cathodoluminescence, and secondary electron signal. Indeed, the space charge region near the Schottky contact exhibits an unusual linear variation with reverse bias whatever the NW radius. On the contrary, the exciton diffusion length is shown to be controlled by the NW radius through surface recombination. This systematic comparison performed on a single ZnO NW demonstrates the power of these complementary techniques in understanding NW properties.
Université Grenoble Alpes , F-38000 Grenoble, France.|CNRS, Institut NEEL , F-38042 Grenoble, France.
F
F
Donatini
Université Grenoble Alpes , F-38000 Grenoble, France.|CNRS, Institut NEEL , F-38042 Grenoble, France.
Andres
A
de Luna Bugallo
Université Grenoble Alpes , F-38000 Grenoble, France.|CNRS, Institut NEEL , F-38042 Grenoble, France.|CEA, LETI , Minatec Campus, F-38054 Grenoble, France.
Pierre
P
Tchoulfian
Université Grenoble Alpes , F-38000 Grenoble, France.|CNRS, Institut NEEL , F-38042 Grenoble, France.
Gauthier
G
Chicot
Groupe d'Etude de la Matière Condensée (GEMAC), CNRS Université de Versailles St. Quentin, Université Paris-Saclay , 78035 Versailles Cedex, France.
Corinne
C
Sartel
Groupe d'Etude de la Matière Condensée (GEMAC), CNRS Université de Versailles St. Quentin, Université Paris-Saclay , 78035 Versailles Cedex, France.
Vincent
V
Sallet
Université Grenoble Alpes , F-38000 Grenoble, France.|CNRS, Institut NEEL , F-38042 Grenoble, France.|Institut Universitaire de France , 103 Boulevard Saint-Michel, F-75005 Paris, France.
Julien
J
Pernot
Nanowire; Schottky; ZnO; cathodoluminescence; electron beam induced current; voltage contrast