Eco-friendly and Recyclable Liquid Metal Synthesis of Two-Dimensional Cr2O3 and CrN Nanosheets for Photoresponse and Field Effect Transistors

In this study, a liquid metal gas injection method was employed to prepare two-dimensional (2D) chromium oxide (Cr2O3) and chromium nitride (CrN). The process, conducted at room temperature and atmospheric pressure, eliminates the need for high temperature and high pressure conditions typically required by conventional methods, thereby reducing energy consumption. The liquid metal used is nontoxic and can be recycled, making the entire experimental procedure environmentally friendly. The resulting amorphous chromium-based semiconductors were transformed to crystalline Cr2O3 and CrN through annealing and nitridation processes. The fabrication and characterization of photodetectors revealed the unique negative photoresponse behavior of Cr2O3 and CrN, with strong correlations to their metallic resistance characteristics confirmed through temperature-resistance measurements. The field-effect transistors demonstrated the p-type semiconductor properties of Cr2O3 and the n-type semiconductor properties of CrN with energy gaps of 3.3 and 0.6 eV, respectively. This research not only illustrates the application of the liquid metal gas injection method for the preparation of two-dimensional materials but also reveals the correlation between negative photoresponse and metallic resistance, providing valuable insights for the future development of photoresponse and contributing to the academic research on 2D materials and their synthesis methods.