Eur. Phys. J. D 25, 25-29 (2003)
https://doi.org/10.1140/epjd/e2003-00081-1

Towards controllable optical response of GaN quantum dots in alumina

¹ INFM, Dipartimento di Fisica, Università di Padova, Via Marzolo 8, 35131 Padova, Italy
² INFM, Dipartimento di Ingegneria dei Materiali, Università di Trento, Via Mesiano 77, 38050 Povo, Trento, Italy
³ INFM, GILDA-CRG ESRF, B.P. 220, 38043 Grenoble, France

Corresponding author: ^a maurizio@padova.infm.it

Received: 23 October 2002
Revised: 20 February 2003
Published online: 24 April 2003

Abstract

GaN nanocrystals (in the wurtzite phase) have been synthesized by thermal annealing in reducing atmosphere of Ga⁺+N⁺ sequentially implanted alumina. We show that the reduction of Ga local concentration (by lowering the implantation dose) yields to an overall increase in the intensity of the GaN photoluminescence signal, to a decrease of the PL bandwidth and to the shift of its onset towards higher energies, due to quantum confinement effects in GaN nanocrystals with a narrow size distribution. The interpretation of the optical results is supported by structural analyses. Moreover, by investigating different forming treatments for GaN synthesis, the key role of hydrogen in the annealing atmosphere is evidenced.