Transferable single-crystal GaN thin films grown on chemical vapor-deposited hexagonal BN sheets

Abstract

Single-crystal gallium nitride (GaN) layers were directly grown on centimeter-scale hexagonal boron nitride (h-BN). Using chemical vapor deposition (CVD), centimeter-scale h-BN films were synthesized on a single-crystal Ni(111) and readily transferred onto amorphous fused silica supporting substrates that had no epitaxial relationship with GaN. For growing fully coalescent GaN layers on h-BN, the achievement of high-density crystal growths was a critical growth step because the sp 2 -bonded h-BN layers are known to be free of dangling bonds. Unlike GaN layers grown on a typical heterogeneous sapphire substrate, the morphological and microstructural results strongly suggest a high-density growth feature that is driven by the atomic cliffs inherent in the CVD-grown h-BN layers. More importantly, the GaN layers grown on CVD-grown h-BN exhibited a flat and continuous surface morphology with well-aligned crystal orientations both along the c-axis and in-plane, indicating the characteristics of GaN heteroepitaxy on h-BN. NPG Asia Materials (2017) 9, e410; doi:10.1038/am.2017.118; published online 28 July 2017 INTRODUCTION There has been significant demand for the fabrication of conventional semiconductor devices in transferable and flexible forms to provide a route for the development of next-generation optoelectronics and electronics. 1-3 Among the various efforts to meet this demand, a new material system has been developed that involves the growth of semiconductor materials directly on twodimensional (2D) layered graphene. Because semiconductors that are grown on graphene layers can be easily transferred to other foreign substrates, including plastic and metal, all cost restrictions arising from substrates can be avoided; 4-7 furthermore, the semimetallic graphene substrates can simultaneously act as current injection and/or spreading layers. Based on these advantages, various group II-VI and III-V semiconductor nanostructures and thin films have been grown on graphene for a range of applications, including light-emitting diodes, solar cells, power generators and sensors. [8][9][10] However, semiconductor heterostructures grown on 2D films still exhibit limited manufacturing scalability because of the difficulty of preparing large-size singlecrystalline 2D substrates. Although single-crystal 2D substrates can ensure that highly crystalline semiconductors can be grown for excellent, uniform device performance, small flakes of mechanically delaminated 2D layered materials are not desirable for practical device applications. In addition, the typical large-scale 2D films synthesized on metal foils by chemical vapor deposition (CVD) are polycrystalline that degrades the crystallinity of the semiconductors grown on CVD-grown 2D films. In this study, we

Cube-Shaped GaN UV Photodetectors Using 3D-Printed Panels for Omnidirectional Detection

“…When the PD was irradiated with 365 nm UV light, the current flowed like an ohmic contact by excited electrons, and the overall current level increased. The X-ray diffraction of the GaN film also exhibited a peak value at 34.56 • , which indicates the high quality of the epitaxial layer [33].…”

Growth of 2D Materials at the Wafer Scale

“…Figure 23d displays one example of vdW epitaxy, demonstrating that the wafer-scale single-crystalline h-BN film was successfully transferred onto disordered fused silica substrate and enabled the mono-oriented GaN epitaxial film growth. [179] More detailed vdW or remote epitaxy techniques have been reviewed in detail in other papers. [183,185] Graphene and h-BN have been reported several times to be used for remote and vdW epitaxial growth.…”

“…For vdW epitaxial growth, multilayer layer graphene and h-BN films have been verified to enable GaN epitaxial growth. [179,185] This process requires the film to be multilayer and lattice monoriented, but less requirement on line and point defects. Mono-oriented multilayer TMDCs films have not yet been confirmed to support vdW epitaxial GaN growth at the wafer scale.…”

Van der Waals Epitaxy of III‐Nitride Semiconductors Based on 2D Materials for Flexible Applications

“…In 2017, Chung et al obtained transferable GaN films on CVD‐grown h‐BN . h‐BN was grown on Ni(111) by CVD and transferred onto SiO 2 substrate, followed by growth of GaN film on the h‐BN/SiO 2 substrate by MOCVD.…”