Pt Nanoparticle-Embedded Single-Crystal Diamond Ultraviolet Detector With Enhanced Responsivity

This study embeds Pt nanoparticles into single-crystal diamond to enhance UV absorption through localized surface plasmon resonance (LSPR), and then a UV photodetector based on Pt-embedded diamond film was investigated. SEM, AFM, and EDS confirmed the dense encapsulation of ~60-nm Pt nanoparticles within the diamond epilayer, preserving its surface flatness and crystalline quality. XPS revealed that the embedded metallic Pt0induced an upward valence band bending. Combined with their partially exposed morphology, these Pt particles acted as a conductive transition layer, facilitating the Ti/diamond ohmic contact. Under 222 nm illumination and -20 V bias, the Pt-embedded detector achieved a responsivity of 8.38 A/W and a UV/visible rejection ratio (R222/R405) of 1.65×104. The device also exhibited comparable response speed to a pure diamond photodetector with rise and fall times of 0.486 s and 2.645 s, respectively. Finite-difference time-domain simulations verified that the performance enhancement primarily originated from the LSPR effect induced by Pt nanoparticles. This work demonstrates metal nanoparticle embedding in single-crystal diamond as an efficient approach for high-performance UV photodetectors.