The influence of dislocations on optical and electrical properties of epitaxial ZnO on Si (111) using a gamma-Al2O3 buffer layer

Abstract

The structural, optical and electrical properties of the c-plane ZnO epitaxial films grown by pulsed laser deposition on a Si(111) substrate buffered with a thin layer of gamma-Al2O3 were investigated by X-ray diffraction, transmission electron microscopy, photoluminescence (PL) and Hall measurements. Detailed structural investigation showed that the dominant structural defects in the ZnO films are threading dislocations (TDs). Experimental results manifest the edge-and screw-type of TDs influence the optical and electric properties differently; the intensity ratio between the PL yellow-green band to near band edge emission and the carrier concentration are affected mainly by the edge TD, and the FWHM of the near band edge emission is dominantly influenced by the screw TD.