Microwave surface transport in narrow-bandgap PdSe2 -MOSFETs
Résumé
Group-10 transition-metal dichalcogenides are puckered van der Waals semiconductors, with a narrow bandgap, envisioned for ultra-broadband infrared (IR) detection. To assess their dynamical transport properties we investigate PdSe 2 n-MOSFETs by using microwave admittance spectroscopy. We report on surface channel inversion-depletion-accumulation behaviors with a depletion length of 15 nm, a mobility of 110 cm 2 V −1 s −1 , and a bulk bandgap of 0.15 eV. Our 10 µm long devices have an electronic cutoff frequency in the GHz range promising a large gain-bandwidth product, competitive with that of III-V (InAs) and II-VI (HgCdTe) devices. The integration of bulk absorption and surface readout in PdSe 2-MOSFETs is a monolithic geometry suitable for fast IR detection in the application-rich 1-10 µm range, which includes molecular spectroscopy, atmospheric communications and thermal sensing.
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