Quest for p-Type Two-Dimensional Semiconductors

Abstract

Two-dimensional (2D) semiconductors have demonstrated great potential in modern nanotechnologies across a variety of research fields, including (opto-)­electronics, spintronics, and electro-/photocatalysis. Interestingly, the vast majority of 2D semiconductors, such as the widely explored transition-metal dichalcogenides, are n-type or ambipolar. The search for p-type 2D semiconductors in the past decade has succeeded in identifying only a few promising candidate materials. In this Perspective, we discuss various strategies to obtain p-type conduction in normally n-type or ambipolar 2D semiconductors and, more importantly, the direct synthesis of p-type 2D semiconductors such as black phosphorus, 2D tellurium, and, most recently, α-MnS.

Two-Dimensional Tellurium: Progress, Challenges, and Prospects

“…The synthesis of large-scale polycrystalline Te flakes was presented through thermal evaporation in the 1960s [76][77][78]. After a prolonged endeavor, Zhao et al have recently demonstrated an exciting breakthrough in the synthesis of highquality 2D Te thin films via this technique [79]. According to their report, Te pellets were used as the thermal vaporation source.…”

Low‐Power Complementary Inverter with Negative Capacitance 2D Semiconductor Transistors

“…exhibit n‐type characteristics, because dichalcogenides vacancies act as n‐type dopant. [ 21–28 ] Even for tungsten diselenide (WSe 2 ) with balanced conduction and valence band edges, it usually exhibits ambipolar transport characteristics without doping. [ 2,5,8,29 ] Thus, it is of great importance to fabricate unipolar p‐type TMD semiconductors FETs to achieve complementary NCFET in a controllable manner.…”

Functional Group‐induced p‐Doping of MoS2 by Titanium(IV) Bis(ammonium lactato) Dihydroxide Physisorption

“…However, there was stubborn n‐type conduction in MoS 2 due to the Fermi level pinning near the conduction band at MoS 2 ‐metal interface induced by intrinsic structure defects and ambient interactions [9,10] . Unipolar n‐type behavior of MoS 2 impeded its practical applications, especially in high performance logic circuits based on complementary metal‐oxide‐semiconductor (CMOS) FETs, in which p‐type FETs were indispensable [11,12] …”