Nonlinear Optical Signatures of the Transition from Semiconductor to Semimetal in PtSe₂

Abstract

The demand for an ultrabroad optical material with a bandgap tunable from zero to at least 1-2 eV has been one of the driving forces for exploring new 2D materials since the emergence of graphene, transition metal dichalcogenides, and black phosphorus. As an ultra-broadband 2D material with energy bandgap ranging from 0 to 1.2 eV, PtSe 2 shows much better air stability than its analogue, black phosphorous. In this work, the superior nonlinear optical performance and ultrafast dynamics of layered PtSe 2 , and signatures of the transition from semiconductor to semimetal are systematically studied. Combining with rate equations, first-principles calculation, and electrical measurements, a comprehensive understanding about the evolution of nonlinear absorption and carrier dynamics with increasing layer thickness is provided, indicating its promising potential in nanophotonic devices such as infrared detectors, optical switches, and saturable absorbers.

Two-Dimensional Platinum Diselenide: Synthesis, Emerging Applications, and Future Challenges

“…Since the pre-deposition process and post-selenization process are carried out in relatively mild condition, the PtSe 2 film can be prepared on arbitrary substrates. Besides the conventional Si [33,115,116], Si/SiO 2 [32,33,55,94,112,114,[117][118][119][120][121][122][123][124], and Sapphire substrate [81,125,126], 2D PtSe 2 film has been successfully grown on fused quartz [31,84,125], fluorine-doped tin oxide (FTO) [127,128], gallium nitride (GaN) [129], and polyimide [114]. Figure 8c shows the PtSe 2 on the surface of flexible polyimide [41,114].…”

Zweidimensionale Edelmetallchalkogenide und ‐phosphochalkogenide

“…Yim et al . stellten einen chemischen Sensor für die NO 2 ‐Gasadsorption her, der ultraschnelle Reaktionszeiten und hohe Empfindlichkeiten aufwies: Nach der Selenisierung von 0.5 nm dickem Pt durch thermisch unterstützte Umwandlung, was zu wechselnden Schichtdicken zwischen 3–5 Lagen führt, reagierte der Sensor nach 10 s Kontakt auf einen 100‐sccm‐Fluss von NO 2 /N 2 ‐Mischgas, wobei der Ursprungswiderstand in reinem N 2 ‐Gas bei Raumtemperatur vollständig wiederhergestellt wurde. Die Autoren fanden Reaktions/Ruhe‐Zeiten von 2.0 zu 53.7 s und 7.4 zu 38.7 s bei 0.1 zu 1.0 ppm NO 2 , mit einer Nachweisgrenze unter 100 ppb.…”

Strong third-order Kerr nonlinearity in 2D PdSe2 dichalcogenide films

“…Similar to the puckered structure of black phosphorus (BP), PdSe2 has a puckered pentagonal atomic structure − with one Pd atom bonding to four Se atoms and two adjacent Se covalently bonding with each other [4]. This low-symmetry structure makes PdSe2 possess unique in-plane anisotropic optical and electronic properties, featuring a noncentrosymmetric (pentagonal) structure, in contrast with its cousin PtSe2 [5,6]. Further, the bandgap of PdSe2 is strongly layer-dependent, varying form 0 eV (bulk) to 1.3 eV (monolayer), a property well suited for photonic and optoelectronic applications [4,7].…”