Effective bandgap engineering in wrinkled germanane via tiny electric field

Abstract

Effective modulation of physical properties via external control is a tantalizing possibility that would bring two-dimensional material-based electronics a step closer. Following the recent experiments, we report a systematic investigation of the effect of external electric field (E-field) on electronic properties of wrinkled germanane based on first-principles calculations. Our results demonstrate that a minuscule E-field can largely and continuously reduce the energy gap of wrinkled germanane. This goes beyond all existing two-dimensional materials, since the required E-field in wrinkled germanane is only a fraction of that for most existing two-dimensional materials. More interestingly, our data show that the promising band inversion can be obtained by modulation of strength of the tiny E-field due to the modification of electron distribution. Furthermore, the possible underlying physical mechanisms are discussed in detail. These results provide a new perspective on the formation of germanane-based electronic devices.