Issue 2, 2020

Optical signatures of single ion tracks in ZnO


The optical properties of single ion tracks have been studied in ZnO implanted with Ge by combining depth-resolved hyperspectral cathodoluminescence (CL) and photoluminescence (PL) spectroscopy techniques. The results indicate that ZnO is susceptible to implantation doses as low as 108 to 109 cm−2. We demonstrate that the intensity ratio of ionized and neutral donor bound exciton emissions [D+X/D0X] can be used as a tracer for a local band bending both at the surface as well as in the crystal bulk along the ion tracks. The hyperspectral CL imaging performed at 80 K with 50 nm resolution over the regions with single ion tracks permitted direct assessment of the minority carrier diffusion length. The radii of distortion and space charge surrounding single ion tracks were estimated from the 2D distributions of defect-related green emission (GE) and excitonic D+X emission, both normalized with regard to neutral D0X emission, i.e., from the [GE/D0X] and [D+X/D0X] ratio maps. Our results indicate that single ion tracks in ZnO can be resolved up to ion doses of the order of 5 × 109 cm−2, in which defect aggregation along the extended defects obstructs signatures of individual tracks.

Graphical abstract: Optical signatures of single ion tracks in ZnO

Supplementary files

Article information

Article type
24 Oct 2019
20 Dec 2019
First published
23 Dec 2019
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2020,2, 724-733

Optical signatures of single ion tracks in ZnO

G. C. Vásquez, K. M. Johansen, A. Galeckas, L. Vines and B. G. Svensson, Nanoscale Adv., 2020, 2, 724 DOI: 10.1039/C9NA00677J

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