使用二维(2D)材料生产独立式膜通常涉及诸如范德华(vdW)外延,准vdW外延,和远程外延。然而,当尝试通过使用这些2D材料辅助生长技术来制造独立式GaN时,出现了挑战。问题在于确保稳定,金属有机化学气相沉积(MOCVD)下的高温生长条件可能由于衬底的GaN分解而对2D材料造成损害。即使使用这种方法成功生长了GaN,对2D材料的损坏导致与基板的直接接合,使生长的GaN的剥离几乎不可能。本研究介绍了一种在2D材料/GaN模板上生长和剥离GaN的方法。首先,将石墨烯和六方氮化硼(h-BN)转移到GaN模板上,在MOCVD中的高温和各种气体下创造稳定的条件。GaN在750和900°C下以两步法生长,确保在二维材料保持完整的情况下剥离。本质上,虽然仅使用MOCVD在2D材料/GaN上生长GaN具有挑战性,这项研究表明,在有效保护二维材料的情况下,生长的GaN可以承受高温,并且仍然会剥落。此外,这些结果支持vdW外延和远程外延原理不仅可以使用特定设备,而且可以普遍应用。
The production of freestanding membranes using two-dimensional (2D) materials often involves techniques such as van der Waals (vdW) epitaxy, quasi-vdW epitaxy, and remote epitaxy. However, a challenge arises when attempting to manufacture freestanding GaN by using these 2D-material-assisted growth techniques. The issue lies in securing stability, as high-temperature growth conditions under metal-organic chemical vapor deposition (
MOCVD) can cause damage to the 2D materials due to GaN decomposition of the substrate. Even when GaN is successfully grown using this method, damage to the 2D material leads to direct bonding with the substrate, making the exfoliation of the grown GaN nearly impossible. This study introduces an approach for GaN growth and exfoliation on 2D material/GaN templates. First, graphene and hexagonal boron nitride (h-BN) were transferred onto the GaN template, creating stable conditions under high temperatures and various gases in
MOCVD. GaN was grown in a two-step process at 750 and 900 °C, ensuring exfoliation in cases where the 2D materials remained intact. Essentially, while it is challenging to grow GaN on 2D material/GaN using only
MOCVD, this study demonstrates that with effective protection of the 2D material, the grown GaN can endure high temperatures and still be exfoliated. Furthermore, these results support that vdW epitaxy and remote epitaxy principle are not only possible with specific equipment but also applicable generally.