An Ultralow Power Mixed Dimensional Heterojunction Transistor Based on the Charge Plasma pn Junction

Development of a reliable doping method for 2D materials is a key issue to adopt the materials in the future microelectronic circuits and to replace the silicon, keeping the Moore's law toward the sub-10 nm channel length. Especially hole doping is highly required, because most of the transition metal dichalcogenides (TMDC) among the 2D materials are electron-doped by sulfur vacancies in their atomic structures. Here, hole doping of a TMDC, tungsten disulfide (WS2) using the silicon substrate as the dopant medium is demonstrated. An ultralow-power current sourcing transistor or a gated WS2 pn diode is fabricated based on a charge plasma pn heterojunction formed between the WS2 thin-film and heavily doped bulk silicon. An ultralow switchable output current down to 0.01 nA mu m(-1), an off-state current of approximate to 1 x 10(-14) A mu m(-1), a static power consumption range of 1 fW mu m(-1)-1 pW mu m(-1), and an output current ratio of 10(3) at 0.1 V supply voltage are achieved. The charge plasma heterojunction allows a stable (less than 3% variation) output current regardless of the gate voltage once it is turned on.