Growth mechanism and optical properties of semiconducting Mg2Si thin films

✍ Scribed by A Vantomme; G Langouche; J.E Mahan; J.P Becker

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 167 KB
• Volume: 50
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(99)00287-7

✦ Synopsis

Reactive deposition of magnesium onto a hot silicon substrate (200-5008C) does not result in any accumulation of magnesium or its silicide -the condensation coefficient of magnesium being zero. On the other hand, codeposition of magnesium with silicon at 2008C, using a magnesium-rich flux ratio, gives a stoichiometric Mg Si film. The number of 2 magnesium atoms which condense is equal to twice the number of silicon atoms which were deposited. The Mg Si layers 2 are polycrystalline with a (111) texture. These stoichiometric silicide films still show a tendency to sublimate; whereas capping with an oxide results in extensive intermixing during annealing. The Mg Si films thus obtained exhibit optical 2 transparency at sufficiently long wavelength, and an absorption edge. Extraction of the absorption coefficient from the data, and analysis of its energy dependence suggest an indirect bandgap of | 0.74 eV, plus direct transitions at | 0.83 and | 0.99 eV.