Is the Bandgap of Bulk PdSe2 Located Truly in the Far‐Infrared Region? Determination by Fourier‐Transform Photocurrent Spectroscopy

• Published in: Advanced photonics research Vol. 3; no. 11
• Main Authors: Nishiyama, Wataru, Nishimura, Tomonori, Nishioka, Masao, Ueno, Keiji, Iwamoto, Satoshi, Nagashio, Kosuke
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley & Sons, Inc 01.11.2022; Wiley-VCH
• Subjects: bandgap determinations; Crystals; Electrons; Fourier-transform photocurrent spectroscopy; Graphene; Light; noble metal dichalcogenides; photothermoelectric effects; photovoltaic effects; Physical properties; Radiation; Semiconductors; Spectrum analysis
• ISSN: 2699-9293; 2699-9293
• DOI: 10.1002/adpr.202200231

2D bulk PdSe2, a group 10 noble metal dichalcogenide, is recognized as a newly found far‐infrared material with a bandgap energy (E G) of ≈0.05 eV and thus has attracted much attention as an optoelectronic material. However, the bandgap energy of bulk PdSe2 is the subject of a controversial debate as a middle bandgap of ≈0.3 eV is also reported by electrical transport measurements. Although determining E G by optical absorption measurement is essential, the difficulty lies in the weak absorption caused by indirect transition. Herein, it is quantitatively estimated that the indirect E G of bulk PdSe2 is indeed 0.5 eV at 40 K based on the highly sensitive spectroscopic method of Fourier‐transformation photocurrent spectroscopy. Herein, it is suggested that the potential application of PdSe2 should be properly selected. The bandgap energy of bulk PdSe2 is the subject of a controversial debate at present. Herein, it is quantitatively estimated that the E G of bulk PdSe2 is 0.5 eV based on Fourier‐transformation photocurrent spectroscopy.