Fig. 2: Doping-band induced unipolarity and Schottky barrier realignment.
From: Uncovering the doping mechanism of nitric oxide in high-performance P-type WSe2 transistors
a Schematic of a 2D field-effect transistor (FET) with a monolayer semiconductor (WSe2) channel, platinum (Pt) metal contacts, and a local bottom gate (LBG) after nitric oxide (NO) doping. The energy band diagram at the semiconductor-contact interface shows how NO doping induces Schottky barrier (SB) realignment via doping-induced pinning (left), while the diagram at the semiconductor-dielectric interface illustrates how the doping band pins the Fermi level (EF) in the off-state (right). Defect bands (blue for acceptor-like traps and red for donor-like traps) are displayed in the gate dielectric and Fermi window (gray) within the semiconductor channel. VBG denotes the back-gate voltage, ΦSB,n and ΦSB,p refer to the Schottky barrier height (SBH) for electrons and holes, respectively, and ΔΦSB represents their change upon NO doping. b ID-VG characteristics at VD = –0.1 V for one representative long-channel device (LCH = 780 nm) prior and post NO doping at 120 °C for 30 min. ID is the drain current, VG is the gate voltage, and VD is the drain-to-source voltage. The blue shaded square marks the region of reduced SBH for holes (ΦSB,p), while the red shaded square indicates increased SBH for electrons (ΦSB,n)and doping-band-induced Fermi level pinning in the bandgap.
