Ultraviolet GaN photodetectors on Si via oxide buffer heterostructures with integrated short period oxide-based distributed Bragg reflectors and leakage suppressing metal-oxide-semiconductor contacts

Abstract

Based on a novel double step oxide buffer heterostructure approach for GaN integration on Si, we present an optimized Metal-Semiconductor-Metal (MSM)-based Ultraviolet (UV) GaN photodetector system with integrated short-period (oxide/Si) Distributed Bragg Reflector (DBR) and leakage suppressing Metal-Oxide-Semiconductor (MOS) electrode contacts. In terms of structural properties, it is demonstrated by in-situ reflection high energy electron diffraction and transmission electron microscopy-energy dispersive x-ray studies that the DBR heterostructure layers grow with high thickness homogeneity and sharp interface structures sufficient for UV applications; only minor Si diffusion into the Y2O3 films is detected under the applied thermal growth budget. As revealed by comparative high resolution x-ray diffraction studies on GaN/oxide buffer/Si systems with and without DBR systems, the final GaN layer structure quality is not significantly influenced by the growth of the integrated DBR heterostructure. In terms of optoelectronic properties, it is demonstrated that—with respect to the basic GaN/oxide/Si system without DBR—the insertion of (a) the DBR heterostructures and (b) dark current suppressing MOS contacts enhances the photoresponsivity below the GaN band-gap related UV cut-off energy by almost up to two orders of magnitude. Given the in-situ oxide passivation capability of grown GaN surfaces and the one order of magnitude lower number of superlattice layers in case of higher refractive index contrast (oxide/Si) systems with respect to classical III-N DBR superlattices, virtual GaN substrates on Si via functional oxide buffer systems are thus a promising robust approach for future GaN-based UV detector technologies.

Remote plasma-enhanced atomic layer deposition of gallium oxide thin films with NH3 plasma pretreatment

“…Therefore, it may be a good solution to replace the native oxides by controllable growth of high quality Ga 2 O 3 . Ga 2 O 3 is a oxide semiconductor or dielectric material with large band gap (4.9 eV) [3] , good thermal and chemical stabilities, and high dielectric constant (10.6) [4,5] . Ga 2 O 3 thin film has been applied in a wide variety of applications, including optoelectronic devices [6] , gas sensor devices [4] , passivation or dielectric layers for III-V based microelectronics [7,8] .…”

Alternative Spectral Photoresponse in a p-Cu2ZnSnS4/n-GaN Heterojunction Photodiode by Modulating Applied Voltage

“…Among lots of wide-bandgap semiconductors, gallium nitride (GaN) has the same wurtzite structure with ZnO and similar wide direct bandgap (3.4 eV). , But few reports were available for the CZTS/GaN heterojunction. Due to the advantages of high saturation velocity (2.7 × 10 7 cm/s), radiation hardness, tolerability of aggressive environments, and a more mature processing technique, GaN was widely used for fabricating photodetectors. − More importantly, the type-I band alignment of the CZTS/GaN interface with a small conduction band offset benefits to carrier separation and transport at the interface, so a p-CZTS/n-GaN heterojunction photodetector is expected to be a promising device with high performance.…”

Highly Reflective Periodic Nanostructure Based on Thermal Evaporated Tungsten Oxide and Calcium Fluoride for Advanced Photonic Applications

“…DBRs have great potential, allowing a wide range of applications such as wavelength filters, , antireflective surfaces, , detectors, − and lasers. − Furthermore, they can be designed to reflect UV radiation in sunglasses, to regulate IR component in smart windows and reduce overheating of indoor environments, to investigate strong light–matter interactions in organic and inorganic microcavities, − to study topological quantum fluids, or to obtain high reflectivity for long-distance propagation of the optical excitation in organic materials . They can also be used in sensing application, − in photovoltaic cells to maximize absorbed light, − in OLEDs to maximize light outcoupling, or to develop devices capable of emitting strong monochromatic light. − …”