Kim Jung Ho, Yun Seok Joon, Lee Hyun Seok, Zhao Jiong, Bouzid Houcine, Lee Young Hee
Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.
Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Sci Rep. 2018 Jul 6;8(1):10284. doi: 10.1038/s41598-018-28323-y.
Layered van der Waals materials have recently attracted attention owing to their exceptional electrical and optical properties in thin layer form. One way to extend their utility is to form a heterostructure which combines various properties of layered materials to reveal intriguing behavior. Conventional heterostructure synthesis methods are difficult to develop and the heterostructure formed can be limited to a small area. Here, we investigate the phase transformation of SnS to SnS by removing sulfur atoms at the top surface using Ar plasma. By varying the plasma power and exposure time, we observed that SnS is subsequently formed on top of the mogul-like structure of SnS. Since SnS is a p-type semiconductor and SnS is an n-type semiconductor, we naturally formed a vertical p-n junction. By using graphene at the top and bottom as transparent electrodes, a vertical p-n diode device is constructed. The device demonstrates good rectifying behavior and large photocurrent generation under white light. This method can be applied to large-area heterostructure synthesis using plasma via phase transformation of various metal dichalcogenides to metal monochalcogenides.
层状范德华材料因其在薄层形式下具有优异的电学和光学性质，近来备受关注。扩展其用途的一种方法是形成异质结构，该结构结合了层状材料的各种特性，展现出有趣的行为。传统的异质结构合成方法难以开发，且形成的异质结构可能局限于小面积。在此，我们通过使用氩等离子体去除顶部表面的硫原子，研究了SnS向SnS的相变。通过改变等离子体功率和暴露时间，我们观察到SnS随后在SnS的大亨状结构顶部形成。由于SnS是p型半导体而SnS是n型半导体，我们自然地形成了垂直p-n结。通过在顶部和底部使用石墨烯作为透明电极，构建了垂直p-n二极管器件。该器件表现出良好的整流行为，并在白光下产生大的光电流。这种方法可通过各种金属二硫属化物向金属单硫属化物的相变，应用于使用等离子体的大面积异质结构合成。
