Fast sweeping for quantum capacitance spectroscopies of two-dimensional materials with microscale spatial resolution

The density of states (DOS) of two-dimensional (2D) materials directly influences the performance of solar cells, sensors, and transistors. The quantum capacitance devices allow for the DOS measurement at room temperature while suffering from complex fabrication processes, with a duration of 5-10 days. It would be meaningful to shorten the measurement time to the hour-level to meet the high-throughput characterization demands in both laboratory research and industrial applications. In this work, we have developed a quantum capacitance spectroscopy (QCS) measurement technique with two orders of improved throughput and microscale spatial resolution. The QCS is further applied to sweep a 4 × 4 array DOS in a MoS2 monolayer with a 100 μm step size. It is able to distinguish the Mo and the coexisting Mo/S vacancies in the MoS2, while the photoluminescence and Raman spectra cannot. This QCS enables the rapid characterization of the DOS, paving the way for screening the defect states in the 2D materials and failure analysis in devices.