Metal-Ion-Modified Black Phosphorus with Enhanced Stability and Transistor Performance

Abstract

Black phosphorus (BP), a burgeoning elemental 2D semiconductor, has aroused increasing scientific and technological interest, especially as a channel material in field-effect transistors (FETs). However, the intrinsic instability of BP causes practical concern and the transistor performance must also be improved. Here, the use of metal-ion modification to enhance both the stability and transistor performance of BP sheets is described. Ag⁺ spontaneously adsorbed on the BP surface via cation–π interactions passivates the lone-pair electrons of P thereby rendering BP more stable in air. Consequently, the Ag⁺-modified BP FET shows greatly enhanced hole mobility from 796 to 1666 cm² V⁻¹ s⁻¹ and ON/OFF ratio from 5.9 × 10⁴ to 2.6 × 10⁶. The mechanisms pertaining to the enhanced stability and transistor performance are discussed and the strategy can be extended to other metal ions such as Fe³⁺, Mg²⁺, and Hg²⁺. Such stable and high-performance BP transistors are crucial to electronic and optoelectronic devices. The stability and semiconducting properties of BP sheets can be enhanced tremendously by this novel strategy.

A simple and effective metal-ion modification strategy based on cation–π interactions is applied to black phosphorus to enhance both its air stability and its transistor performance. Such stable and high-performance black-phosphorus transistors, which are enhanced tremendously by this novel strategy, have large potential in electronic and optoelectronic devices.

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