Effects of short-term exposure of monocrystalline HfSe2 surface to air

One way to improve silicon-based electronics is to integrate silicon into a material that has properties such as an energy gap in the 1-2 eV range and high charge carrier mobility. A material that meets these requirements is HfSe2, which belongs to the group of transition metal dichalcogenides (TMDs). A key aspect concerning the possible use of HfSe2 in electronics is its oxidation.

In the article „𝗧𝗵𝗲 𝗲𝗳𝗳𝗲𝗰𝘁𝘀 𝗼𝗳 𝘀𝗵𝗼𝗿𝘁-𝘁𝗲𝗿𝗺 𝗮𝗶𝗿 𝗲𝘅𝗽𝗼𝘀𝘂𝗿𝗲 𝗼𝗳 𝘁𝗵𝗲 𝗺𝗼𝗻𝗼𝗰𝗿𝘆𝘀𝘁𝗮𝗹 𝗛𝗳𝗦𝗲𝟮 𝘀𝘂𝗿𝗳𝗮𝗰𝗲”, the authors presented a study of the dynamics of early oxidation of HfSe2 surfaces during exposure to weathering using techniques such as SEM, EDX, XPS, and RS. Experimental results are backed by the results of DFT calculations of the O/HfSe2 adsorption system. The study shows a rapid transformation of the surface with the formation of Se-rich round structures, whose coverage increases with exposure time. It is related to an intense diffusion of Se atoms, with the simultaneous penetration of O atoms deep into the crystal, leading to the formation of a layer of HfO2 in the subsurface region.