Microwave irradiation-assisted deposition of Ga_2O_3 on Ill-nitrides for deep-UV opto-electronics

摘要

We report on the deposition of Ga_2O_3 on Ill-nitride epi-layers using the microwave irradiation technique. We also report on the demonstration of a Ga_2O_3 device: a visible-blind, deep-UV detector, with a GaN-based heterostructure as the substrate. The film deposited in the solution medium, at <200 ℃, using a metalorganic precursor, was nanocrystalline. XRD confirms that the as-deposited film, when annealed at high temperature, turns to polycrystalline β—Ga_2O_3. SEM shows the as-deposited film to be uniform, with a surface roughness of 4-5 nm, as revealed by AFM. Interdigitated metal-semiconductor-metal devices with Ni/Au contact exhibited a peak spectral response at 230 nm and a good visible rejection ratio. This demonstration of a deep-UV detector on the β—Ga_2O_3/III-nitride stack is expected to open up possibilities of functional and physical integration of β—Ga_2O_3 and GaN material families towards enabling next-generation high-performance devices by exciting band and heterostructure engineering.