Patterned buffer layer promotes maskless lateral epitaxial overgrowth of low-dislocation-density ZnO films in aqueous solution at low temperature

摘要

In this article, we describe a facile approach, with the assistance of a stripe-patterned ZnAl_2O_4 buffer layer, for the maskless lateral epitaxial growth (LEO) of low-dislocation-density ZnO films. During hydrothermal processing, the selective-area epitaxial growth of ZnO mesas occurred preferentially on ZnAl_2O_4 stripes. The ZnO growth subsequently occurred in the lateral direction; eventually, adjacent stripe-patterned ZnO mesas coalesced to form a continuous film. The dislocation density at the coalesced LEO ZnO was 10~8 cm~(-2). The photoluminescence of LEO-grown ZnO films featured a strong near-band-edge ultraviolet emission, but other defect-related visible emissions were suppressed almost entirely, indicating a significant improvement in crystalline quality.