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arXiv · 1506.07217

Shallow carrier traps in hydrothermal ZnO crystals

C. Ton-That·L. L. C. Lem·M. R. Phillips·F. Reisdorffer·J. Mevellec·T. -P. Nguyen·C. Nenstiel·A. Hoffmann
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Abstract

Native and hydrogen-plasma induced shallow traps in hydrothermally grown ZnO crystals have been investigated by charge-based deep level transient spectroscopy (Q-DLTS), photoluminescence and cathodoluminescence microanalysis. The as-grown ZnO exhibits a trap state at 23 meV, while H-doped ZnO produced by plasma doping shows two levels at 22 meV and 11 meV below the conduction band. As-grown ZnO displays the expected thermal decay of bound excitons with increasing temperature from 7 K, while we observed an anomalous behaviour of the excitonic emission in H-doped ZnO, in which its intensity increases with increasing temperature in the range 140-300 K. Based on a multitude of optical results, a qualitative model is developed which explains the Y line structural defects, which act as an electron trap with an activation energy of 11 meV, being responsible for the anomalous temperature-dependent cathodoluminescence of H-doped ZnO.

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C. Ton-That, L. L. C. Lem, M. R. Phillips, F. Reisdorffer, J. Mevellec, T. -P. Nguyen, C. Nenstiel, A. Hoffmann. 2015-06-24. Shallow carrier traps in hydrothermal ZnO crystals. https://doi.org/10.1088/1367-2630/16/8/083040

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