We report on the pulsed laser-induced dewetting (LID) process of Co/sapphire(0001) thin films in water environment. In contrast to LID in a vacuum, where only Co nanoparticles (NPs) are formed, a 12nm thick Co film was dewetted into a mixture of crystalline CoO NPs and nanowalls (NWs). The formation of the CoO NPs can be explained by the grooving model occurring concurrent with the oxidation of Co to CoO. Possible scenarios for the formation of NWs are proposed. The dissolution of Co into water occurred near the hole area. Upon subsequent laser irradiation, and O²⁻ ions abundant in water facilitate the laser-induced hydrothermal process (LIHP) producing CoO NWs. Furthermore, we found that the combination of dissolution and LIHP is energetically more favorable over dewetting in a 4.8nm thick sample, where only CoO NWs were observed. Finally, the reduction of sapphire substrate is revealed by the formation of Al-rich NPs.

我们报告了在水环境中Co /蓝宝石（0001）薄膜的脉冲激光诱导去湿（LID）过程。与在真空中仅形成Co纳米颗粒（NP）的LID相比，将12nm厚的Co膜浸润成结晶CoO NP和纳米壁（NW）的混合物。CoO NP的形成可以通过与Co氧化为CoO同时发生的切槽模型来解释。提出了形成NW的可能方案。Co在孔附近附近溶解到水中。在随后的激光照射下，O ²⁻水中富含的离子有助于产生CoO NW的激光诱导水热过程（LIHP）。此外，我们发现，在仅观察到CoO NW的4.8nm厚度的样品中，溶解和LIHP的结合在能量上比反润湿更有利。最后，通过富铝纳米颗粒的形成揭示了蓝宝石衬底的减少。