Temperature-dependent phonon mode and interband electronic transition evolutions of ε-InSe films derived by pulsed laser deposition

Abstract

We report the temperature-dependent phonon modes and interband electronic transitions of InSe films on SiO2/Si substrates prepared by pulsed laser deposition. The microstructure results proved the ε phase structure and monochalcogenide phase composition with well-defined hexagonal InSe sheets. The temperature effects on lattice vibrations were discovered by Raman spectra from 123 K to 423 K. The frequency and full width at half maximum of the A2g1(LO) mode show a strong nonlinearity with the temperature. The energy band structure and electron–phonon interaction were studied by temperature-dependent spectroscopic ellipsometry with the aid of the Tauc–Lorentz model. It was found that five electronic transitions around 1.33, 1.61, 2.53, 3.73, and 4.64 eV generally show a redshift trend with the temperature. The present results can provide a valuable reference for future optoelectronic applications of InSe films.

Tunable lattice dynamics and dielectric functions of two-dimensional Bi2O2Se: striking layer and temperature dependent effects

“…A three-layer optical model (air/Bi 2 O 2 Se/sapphire) was constructed and the parameterized dispersive model consisting of Tauc–Lorentz and Lorentz oscillators was used for the fitting. 29–31 The fitted results are in good agreement with the obtained curves from Bi 2 O 2 Se, as shown in Fig. 4a, b and Fig.…”