Nanoscale electromechanical and electronic properties of free-standing ZnO nano- and microstructured platelets

• Published in: Nanotechnology Vol. 28; no. 40; pp. 405701 - 405705
• Main Authors: Faraji, N, Adelung, R, Mishra, Y K, Seidel, J
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 06.10.2017
• Subjects: electrical properties; grain boundaries; scanning probe microscopy; surface potential; zinc oxide
• ISSN: 0957-4484; 1361-6528; 1361-6528
• DOI: 10.1088/1361-6528/aa87f8

The piezoelectric response, conductivity and surface potential of individual grains and grain boundaries in free-standing polycrystalline ZnO nano- and microstructured platelets is studied using scanning probe based techniques on the nanoscale. We find that applied dc electric fields can alter the piezoresponse in individual grains, as well as the local nanoscale conductivity, and invert the relative surface potential at grain boundaries. This can be attributed to defect accumulation at the grain surfaces and at grain boundaries and the associated density of carriers. Together with recently observed below-bandgap photoconductivity at grain boundaries, the presented observation opens new venues for potential nanoelectronic applications that rely on grain and grain boundary engineering and functionality in a wide-bandgap transparent material.