The energy bandgap is an intrinsic character of semiconductors, which largely
determines their properties. The ability to continuously and reversibly tune
the bandgap of a single device during real time operation is of great
importance not only to device physics but also to technological applications.
Here we demonstrate a widely tunable bandgap of few-layer black phosphorus (BP)
by the application of vertical electric field in dual-gated BP field-effect
transistors. A total bandgap reduction of 124 meV is observed when the
electrical displacement field is increased from 0.10V/nm to 0.83V/nm. Our
results suggest appealing potential for few-layer BP as a tunable bandgap
material in infrared optoelectronics, thermoelectric power generation and
thermal imaging.Comment: 5 pages, 4 figure
