Mn-Doped Ge Nanoparticles Grown on SiO<sub>2</sub> Thin Films by Molecular Beam Epitaxy for Photodetector and Solar Cell Applications
Mansour Aouassa, Mohammed Bouabdellaoui, Makrem Yahyaoui, T. Kallel, Thouraya Ettaghzouti, Saud A. Algarni, Ibrahim O. Althobaiti
Abstract
In this work, we propose a novel efficient strategy based on the combination of molecular beam epitaxy deposition and the solid-state dewetting process for the growth and self-assembly of magnetic GeMn nanoparticles on the SiO 2 substrate. Morphological and structural investigations of magnetic GeMn nanoparticles carried out by AFM and HR-TEM microcopies show that these nanoparticles are very dense (10 12 cm –2 ), are homogeneous, and have a free-defect single-crystalline Ge-Mn phase. The investigations of the magnetic properties carried out by a superconducting quantum interference device (SQUID) reveal that our magnetic GeMn nanoparticles are ferromagnetic and have a Curie record temperature of 325 K. The electrical characterizations of these GeMn nanoparticles when they are inserted in the insulator layer of a metal–insulator–semiconductor Schottky diode show that the nanoparticles contribute to electrical transport and photo-generation of hole–electron pairs when illuminated by white light, resulting in a significant increase in photocurrent of the order of 10 times. This novel growth strategy, which is compatible with CMOS technology, represents a promising path toward the real incorporation of diluted magnetic GeMn nanostructures in photodetection and photovoltaic technologies.