Phase transformation from FeSe to Fe3Se4

We report on thermal atomic layer deposition of iron selenide (FeSe and Fe3Se4) thin films with four-inch wafer-scale uniformity using two precursors of iron bis(N, N '-diisopropylacetamidinato) [Fe(i-Pr-MeAMD)2] and bis(triethysilyl) selenide [(Et3Si)2Se]. The temperature window is determined to be 350-400 degrees C. The transformation from tetragonal FeSe to monoclinic Fe3Se4 has been found. The tetragonal FeSe thin films exhibit a strong (00 l) texture deposited on amorphous silica glass, suggesting that the surface is partially parallel to the layered ab plane. By adjusting the ratio of iron and selenium, the thin films exhibit from conductors to semiconductors, and finally to insulators. All as-grown conductive samples appear metallic-like temperature dependence by low-temperature electrical transport measurements. This study opens the way to prepare various metal selenides by atomic layer deposition. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, thermal atomic layer deposition was used to fabricate iron selenide thin films (FeSe and Fe3Se4) with four-inch wafer-scale uniformity. Two precursors, iron bis(N, N'-diisopropylacetamidinato) [Fe(i-Pr-MeAMD)2] and bis(triethysilyl) selenide [(Et3Si)2Se], were employed. The films were grown within the temperature range of 350-400 degrees C and exhibited a transformation from tetragonal FeSe to monoclinic Fe3Se4. By adjusting the ratio of iron and selenium, the films exhibited varying conductivity properties, transitioning from conductors to semiconductors and finally to insulators. This study opens up new possibilities for preparing metal selenides through atomic layer deposition.