Localized surface plasmon resonance enhanced deep ultraviolet photodetectors based on Pd@Nb2CTx/AlGaN van der Waals heterojunctions

Localized surface plasmon resonance (LSPR) has been proven as an effective means to improve the performance of optoelectronic devices from infrared to ultraviolet region. However, due to the lack of suitable plasmon materials in the deep ultraviolet (DUV) region, studies in this field were relatively rare. Herein, a simple solution reduction method was proposed to decorate palladium nanoparticles (Pd NPs) onto two-dimensional (2D) niobium carbide Nb2CTx (MXene) nanosheets to fabricate Pd@Nb2CTx/aluminum-gallium nitride (AlGaN) van der Waals heterojunction (vdWH) DUV photodetectors (PDs). Thanks to the plasmon coupling between Pd@Nb2CTx and AlGaN, the obvious enhanced optical absorption and carrier excitation of the as-fabricated DUV PDs have been observed with a peak responsivity of 0.86 A/W, as well as a fast response (rise/decay time of 37.8/14.5 ms) under −3 V bias and 254 nm DUV illumination. This study provides direct evidence for LSPR of Pd NPs in the DUV region, which will develop an optional pathway for the structure design of DUV PDs.