Multi-Bit Analog Transmission Enabled by Electrostatically Reconfigurable Ambipolar and Anti-Ambipolar Transport.

Various analog applications, such as phase switching, have been demonstrated using either ambipolar or anti-ambipolar transport in two-dimensional materials. However, the availability of only one transport mode severely limits the application scope and range. This work demonstrates electrostatically reconfigurable and tunable ambipolar and anti-ambipolar transport in the same field-effect transistor using a photoactive ambipolar WSe2 channel with gate-controlled channel and Schottky barriers. This enables the realization of in-phase, out-of-phase, and double-frequency sinusoidal output signals under dark and illumination conditions. The output waveforms were used to generate phase-, frequency-, and amplitude-modulated analog schemes for 2- and 3-bit data transmission. Evaluation of all possible schemes for their power consumption, error probability, and implementation complexity highlights the importance of switching between ambipolar and anti-ambipolar modes of transport for best transmission performance. A dual-metal contact transistor with improved linearity for harmonic and excess power suppression demonstrates further performance enhancement. Generic device architecture and operation makes this work adaptable to any ambipolar material amenable to electrostatic control.