Formation of 2D-Structured InSe Ceramics from Amorphous Phase Deposited on a Kapton Foil

Abstract

The formation kinetics of the 2D-layered InSe crystalline phase in thin amorphous InSe films was studied by means of differential scanning calorimetry, Raman spectroscopy, X-ray diffraction analysis, and X-ray absorption spectroscopy. All measurements were performed on as-deposited films (thicknesses ranging between 200 and 1500 nm), with Kapton foil used as a substrate. In the films with thickness ≥ 1000 nm, the formation was found to proceed via two steps: the exothermic reorganization of the amorphous phase (activation energy of 420 kJ•mol −1 ), followed by the exothermic formation of the crystalline phase (activation energy of 227 kJ•mol −1 ). For InSe films with thickness ≤ 500 nm, the two processes merged, but their reaction mechanism was still found to consist of two sequential phase transformations, with the reorganization in the amorphous phase being the necessary preliminary step. Both kinetic processes were found to be slowed down by the presence of mechanical defects and by the surface/interface imperfections. The possibility of two-step preparation of ideally layered flexible 2D InSe ceramics is suggested based on the separated hightemperature amorphous phase reorganization, followed by a low-temperature crystal growth step (during which excellent 2D InSe layering could be achieved).

Native Crystal Growth Revealed by a Joint Microscopy–Calorimetry Technique in (GeS2)0.1(Sb2S3)0.9 Thin Amorphous Films: A Critical Role of Internal Stress and Mechanical Defects

“…Such measurements did not have the potential to reveal the intricacies associated with the aforementioned aspects influencing the crystal growth in chalcogenide thin films. This was changed only recently − by the development of a joint instrumental setup, where the microscopic and calorimetric (specifically using differential scanning calorimetry (DSC)) measurements were performed under identical conditions on as-deposited thin films (i.e., films still attached to the substrate). The high variability of the applicable experimental conditions (achieved by employing DSC in the preparation of samples for microscopy) together with the in situ DSC measurements of as-deposited films represent a huge step forward, compared to the previous approaches limited to the inaccurate and poorly controlled preparation of the microscopic samples and to the DSC measurements of massively altered (scratched-off of the substrates) films.…”

Fast crystallization of InSe thin films via pulsed laser welding technique and effect of crystallinity on the optical and dielectric properties

“…As grown InSe thin films prefer the amorphous nature of growth [6][7][8]. Films deposited by the thermal evaporation technique onto amorphous substrates (glass) showed amorphous nature of growth [6].…”

“…Films deposited by the thermal evaporation technique onto amorphous substrates (glass) showed amorphous nature of growth [6]. Films coated by the pulsed laser deposition technique onto a Kapton foil were also amorphous in nature [7]. Crystallinity of these films is reached via temperature dependent exothermic re-organization of the amorphous phase followed by exothermic formation of crystalline phase [7].…”

“…Films coated by the pulsed laser deposition technique onto a Kapton foil were also amorphous in nature [7]. Crystallinity of these films is reached via temperature dependent exothermic re-organization of the amorphous phase followed by exothermic formation of crystalline phase [7]. The crystallinity process needed few hours [7] to be reached.…”

“…Crystallinity of these films is reached via temperature dependent exothermic re-organization of the amorphous phase followed by exothermic formation of crystalline phase [7]. The crystallinity process needed few hours [7] to be reached. In addition multi-crystallization process in amorphous InSe is achieved via heating process in the temperature range of 25 °C-400 °C [8].…”