Epitaxial growth of GaN on single-crystal Mo substrates using HfN buffer layers

GaN films have been grown on single-crystalline Mo substrates using lattice-matched HfN buffer layers, and their structural properties have been investigated. Although it is not possible to grow high-quality GaN films on either Mo(1 1 0) or (1 1 1) substrates, high-quality epitaxial GaN(0 0 0 1) films with atomically flat surfaces can be grown on the HfN(1 1 1)/Mo(1 1 0) structure with an in-plane alignment of GaN[1 1 2¯ 0] ∥ HfN[1 1¯ 0] ∥ Mo[0 0 1]. We have also found that the HfN/Mo heterointerface is quite abrupt. These results indicate that Mo(1 1 0) substrates with HfN buffer layers are promising candidates for the fabrication of future light-emitting devices (LEDs).