Hybrid heterostructures based on bulk GaN and two-dimensional (2D) materials offer novel paths toward nanoelectronic devices with engineered features. Here, we study the electronic properties of a mixed-dimensional heterostructure composed of intrinsic $n$-doped $\mathrm{Mo}{\mathrm{S}}_2$ flakes transferred on $p$-doped GaN(0001) layers. Based on angle-resolved photoemission spectroscopy (ARPES) and high resolution x-ray photoemission spectroscopy (HR-XPS), we investigate the electronic structure modification induced by the interlayer interactions in $\mathrm{Mo}{\mathrm{S}}_2/\mathrm{GaN}$ heterostructure. In particular, a shift of the valence band with respect to the Fermi level for $\mathrm{Mo}{\mathrm{S}}_2/\mathrm{GaN}$ heterostructure is observed, which is the signature of a charge transfer from the 2D monolayer $\mathrm{Mo}{\mathrm{S}}_2$ to GaN. The ARPES and HR-XPS revealed an interface dipole associated with local charge transfer from the GaN layer to the $\mathrm{Mo}{\mathrm{S}}_2$ monolayer. Valence and conduction band offsets between $\mathrm{Mo}{\mathrm{S}}_2$ and GaN are determined to be 0.77 and $-0.51\mathrm{eV}$, respectively. Based on the measured work functions and band bendings, we establish the formation of an interface dipole between GaN and $\mathrm{Mo}{\mathrm{S}}_2$ of 0.2 eV.

• Received 26 June 2017

DOI:https://doi.org/10.1103/PhysRevB.96.115312