magnesium selenide formula (Se-Mg) can be characterized in terms of electronic properties and crystalline phase by DFT calculations. The valence band structure, phonon dispersion and phonon density of states for MgSe with crystalline phases of ZB, WZ, RS and NiAs are computed, using self-consistent local density approximation.
The ligand compound may be a carboxylic acid, an alkyl alcohol or a hydroxyl compound. The ligand compound may be dissolved in the solvent and injected into a reactor containing the first precursor. Then, the ligand compound may react with the Se-containing second precursor in a reaction that forms a Mg-Se nanocrystal.
One or more of the ligand compounds that may be present in the method may contain an oxygen functional group, which will act as an oxygen source in the reaction system. The oxophilic nature of magnesium will cause the oxygen-containing compound to bond with the Mg-Se nanocrystal to form an extremely stable oxide.
In the case of a wet chemical process, such as MBE, the oxophilic character of magnesium is exacerbated since the oxygen-containing ligand compound may be reacted with Mg-Se, forming an oxide that will bond very tightly to the Mg-Se cation. As a result, synthesis of Mg-Se nanocrystals via wet chemical processes may be challenging.
In order to overcome this challenge, we have developed a new procedure that involves the use of a ligand compound that does not contain an oxygen functional group. This ligand compound is dissolved in the solvent and then injected into a reaction chamber containing the Mg-containing first precursor and the Se-containing second precursor. Then, the ligand and the solvent are heated under vacuum to remove the oxygen source substantially completely. Then, the Mg-containing first precursor and the selenium-containing second precursor are reacted in the reaction chamber to form a Mg-Se nanocrystal.