Oxidation behavior with quantum dots formation from amorphous GaAs thin films

ABSTRACT

We investigated the oxidation behaviour of an amorphous GaAs thin film deposited onto a micro/nanotextured Si surface by an electron beam. After the deposited film was exposed to air, microcrystallites were formed with octahedral cubic and monoclinic structures of arsenic oxides. Short time exposure after thin film deposition showed the formation of cubic arsenolite while long time exposure showed the formation of monoclinic claudetites as well as cubic arsenolites. These oxide microcrystallites at the GaAs thin film surface disappeared after the sample annealing process. However, the amorphous GaAs thin film included high-density GaAs nanodots. From UV and inverse photoemission spectroscopies, the thin film showed n-type band structure with an energy gap of 2.73 eV. Photoluminescence measurement showed an emission peak at (450–513) nm with the energy of (2.41–2.75) eV corresponding to dot size of (4.1–4.5) nm.

KEYWORDS:

• Amorphous GaAs thin film
• arsenic oxide microcrystallites
• arsenoid molecular cages
• pyramidal arsenolite

Acknowledgments

This research was supported by a grant (NRF-2014R1A1A2056184) of the Basic Science Research Programme through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Republic of Korea.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Keunjoo Kim http://orcid.org/0000-0002-5103-699X

Additional information

Funding

This research was supported by a [grant number NRF-2014R1A1A2056184] of the Basic Science Research Programme through the National Research Foundation of Korea (NRF), funded by the Ministry of Education of the Republic of Korea.