Sample preparation induced phase transitions in solution deposited copper selenide thin films
Bar Koren1,2, Ofir Friedman1,2, Nitzan Maman2
1Department of Materials Engineering, Ben-Gurion University of the Negev Beer-Sheva 8410501 Israel ygolan@bgu.ac.il.
RSC Advances
|April 15, 2022
Summary
Copper selenide (CuSe) thin films unexpectedly transformed into the β-Cu2-Se phase due to selenium loss during specimen preparation. This phase transition was also induced by heat and electron beams, highlighting the sensitivity of copper selenide phases.
Area of Science:
- Materials Science
- Solid State Chemistry
- Thin Film Deposition
Background:
- Copper selenide (CuSe) thin films were deposited on gallium arsenide (GaAs) substrates.
- Initial characterization suggested the Klockmannite (CuSe) phase.
Purpose of the Study:
- Investigate phase discrepancies observed in deposited CuSe thin films.
- Understand the factors influencing phase transitions in copper selenide systems.
Main Methods:
- X-ray Diffraction (XRD) for initial phase identification.
- Transmission Electron Microscopy (TEM) with electron diffraction for detailed structural analysis.
- Focused Ion Beam (FIB) for specimen preparation.
- Thermal treatment in vacuum.
Main Results:
- XRD indicated the Klockmannite (CuSe) phase, while TEM revealed the β-Cu2-Se phase.
- Selenium loss during FIB preparation triggered a phase transition to β-Cu2-Se.
- Thermal treatment and electron beam irradiation also induced the phase transition.
- Altering reactant composition allowed co-existence of cubic α-Cu2-Se and β-Cu2-Se phases.
Conclusions:
- Specimen preparation methods significantly impact the observed phase of copper selenide thin films.
- Selenium volatility is a critical factor in phase stability and transitions.
- Controlled deposition conditions can influence the resulting phase composition.
Related Concept Videos
01:17Precipitation and Co-precipitation
2.3K
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
2.3K
01:20Preparation of Samples for Electron Microscopy
6.0K
To be visualized by an electron microscope, either transmission or scanning, biological samples need to be fixed (stabilized) so the electron beam does not destroy them and dried thoroughly (desiccated/dehydrated) so the vacuum does not affect them. Fixation needs to be done as quickly as possible because the sample properties will start changing as soon as it is removed from its natural environment. For example, in a tissue sample, the oxygen levels begin decreasing, causing an altered...
6.0K