Van der Waals contacted MoO_x staked ZnO/GaN vertical heterostructured ultraviolet light emitting diodes

Since the discovery of two dimensional (2D) materials, there has been a gold rush for van der Waals integrated 2D material heterostructure based optoelectronic devices. Van der Waals integration involves the physical assembly of the components of the device. In the present work, we extended van der Waals integration from 2D materials to three-dimensional (3D) materials, and herein we uniquely designed a van der Waals contacted light emitting diode based on MoO_x staked ZnO/GaN heterostructure. The presence of the MoO_x layer between n-type ZnO and p-type GaN leads to the confinement of electrons and an increase in the electron charge density at n-type ZnO. The n-type MoO_x, a well-known hole injection layer, favors the availability of holes at the ZnO site, leading to the efficient recombination of electrons and holes at the ZnO site, which results in predominant high-intensity UV-EL emission around 380 nm in both forward and reverse bias.