Flow modulation epitaxy of hexagonal boron nitride
Flow modulation epitaxy of hexagonal boron nitride
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DOI：
10.1088/2053-1583/aad5aa
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发表时间：
2018-10-01
期刊：
影响因子：
5.5
通讯作者：
Jagadish, C.
中科院分区：
文献类型：
--
作者：
Chugh, D.;Wong-Leung, J.;Jagadish, C.
本文报道了用金属有机物气相外延法在2 "蓝宝石衬底上生长六方氮化硼（hBN）层，并比较了连续流动和流动调制（FM）两种方案下的生长情况。在连续流动状态下生长的hBN膜由于前体分子之间的严重寄生反应而表现出低的生长速率和粗糙的表面轮廓，这通过采用FM方案来抑制。我们还观察到自发分层的hBN膜从基板时，浸泡在水浴和属性这是由于在膜中的压缩应力的松弛，这是进一步证实了使用拉曼光谱。碳被确定为主要杂质，其在FM生长下作为碳化硼被并入，并导致在1.77-2.25 eV范围内的大的亚带隙荧光。总体而言，在本研究中，使用FM方案在低生长速率（类似于2-3 nm h（-1））下沉积的hBN膜表现出最好的特性，这将适用于诸如货车德瓦尔斯外延和2D异质结构器件的应用。
Growth of hexagonal boron nitride (hBN) layers on 2 '' sapphire substrate using metal organic vapour phase epitaxy is reported here, where we compare the growth under continuous flow and flow modulation (FM) schemes. hBN films grown under the continuous flow regime exhibit low growth rate and rough surface profiles due to severe parasitic reactions between precursor molecules, which are suppressed by adopting a FM scheme. We also observe spontaneous delamination of hBN films from the substrate when immersed in a water bath and attribute this to be due to relaxation of compressive stress in the films, which was further corroborated using Raman spectroscopy. Carbon is identified as a major impurity which gets incorporated as boron carbide under FM growth and results in large sub-bandgap fluorescence in the range of 1.77-2.25 eV. Overall, hBN films deposited using the FM scheme at low growth rate (similar to 2-3 nm h(-1)) exhibited the best characteristics in the present study, which will be suitable for applications such as van der Waals epitaxy and 2D heterostructure devices.