Quantum capacitance measurement for a black phosphorus field-effect transistor

The unique electrical, optical and thermal properties of black phosphorus have triggered the development of black phosphorus transistors as well as a wide range of other relevant applications. However, there are still challenges in understanding and modeling gated black phosphorus, among which the exploration of quantum capacitance is crucial. Understanding quantum capacitance requires specified measurements other than typical characterizations done before for black phosphorus transistors. Recently, Kuiri et al (Nanotechnology 26 485704) reported the quantum capacitance measured on few layer black phosphorus and its difference compared to that from conductance measurement. Localized states near the band edge were observed by the capacitance measurement, which was considered as the main reason for the difference. The new findings provide guidelines for theoretical understanding and modeling of black phosphorus devices.