Anisotropic High Carrier Mobility in Violet Phosphorus

Violet phosphorus (VP), with its high carrier mobility, is a promising candidate for next-generation optoelectronic devices. Its anisotropic structure, polarization sensitivity, high photoelectric efficiency, and tunable bandgap enable diverse optical responses, making it ideal for applications such as photodetectors, neural networks, and multimodal systems. However, the basic anisotropic transport properties have not been experimentally revealed. Here, we report the anisotropic transport behavior of VP nanosheets using polarized transient absorption microscopy. The ambipolar mobility along the a-axis reaches ∼2100 cm²V^-1s^-1, significantly higher than the b-axis mobility of ∼380 cm²V^-1s^-1, yielding a diffusion anisotropy ratio of 5.5:1. Steady-state optical techniques further indicate that anisotropy in the deformation potential plays a key role in this behavior. This study clarifies the intrinsic mechanism of anisotropic carrier transport in VP and offers theoretical insight for designing angle-sensitive optoelectronic devices.