Controlled <i>p</i>-type Doping of Black Phosphorus Using AuCl<sub>3</sub> Molecules and Its Diode Applications

Abstract

Modulating reliable doping of two-dimensional (2D) black phosphorus (BP) is crucial for building complementary logic devices based on BP channels. However, most studies on doping techniques for BP devices have aimed to realize n-type doping effect rather than p-type one. Herein, we demonstrate AuCl3 molecular doping of BP devices to realize the p-type doping effect. After AuCl3 doping on BP, small Au nanoparticles are formed on the surface of BP flakes. Such AuCl3 -doped BP devices exhibit a clear transition from ambipolar to unipolar behaviors (p-type characteristics) as doping time gradually increases. This p-type doping effect originates from the electron withdraw ability due to the spontaneous interaction between the AuCl3 and unpaired electrons in BP. Using our doping strategy, we fabricate 2D diode devices consisting of a molybdenum disulfide (MoS2) monolayer and BP flakes. We confirm a clear rectifying behavior, which is more enhanced using AuCl3-doped BP devices, compared with pristine BP one. Consequently, these devices exhibited good responsivity of 2.4 A W-1 and detectivity of 2.5 x 10(11) Jones, when illuminated with 530 nm light. [GRAPHICS] .