Electromechanical behaviour of violet phosphorene nanoflakes.

Violet phosphorene (vP), a two-dimensional structure with various unique properties, has attracted much attention recently. The electromechanical behaviour, a mechanical-electrical-thermal coupling failure behaviour, of supported and suspended vP nanoflakes has been investigated by the c-AFM nanoindentation method under different loads and bias voltages in this work. A bump due to the oxidation caused by electric current-induced local heating was observed for the supported vP on substrates under mild load and bias voltage. A concave morphology was observed when a load of 1500 nN and a bias voltage of 10 V were applied. No bump was observed for the suspended vP due to the larger contact area between the probe and the sample, resulting in a lower temperature. Fatigue damage was observed for the vP nanoflakes under constant load and a cycled bias voltage from 10 V to -10 V. The electromechanical behaviour of vP was also analyzed through its specific heat capacity and conductivity by density functional theory.