Fabrication and characterization of Mn-implanted GaN layers followed by annealing
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RESEARCH
Fabrication and characterization of Mn‑implanted GaN layers followed by annealing Im Taek Yoon1 · Dejun Fu2 Received: 16 August 2020 / Accepted: 21 October 2020 © Islamic Azad University 2020
Abstract We report the effect of Mn incorporation on the structural and optical properties of GaN grown on a sapphire substrate in a plasma-enhanced molecular-beam epitaxy system followed by Mn ion implantation and annealing. The crystalline quality and phase purity were determined by high-resolution X-ray diffraction (XRD). The XRD results indicated that no macroscopic second phases were present in the Mn-implanted GaN layer after the annealing process. High-resolution transmission microscopy and energy dispersive X-ray spectroscopy revealed that the as-grown GaN epilayer and Mn-implanted GaN layer after annealing were single crystals with a hexagonal wurtzite structure, and they grew with a c-axis orientation perpendicular to the sapphire substrate. The Raman and photoluminescence spectra showed that the Mn-implanted GaN layer fabricated with a Mn ion dose of 5 × 1015 cm−2 followed by annealing at 800 °C for 30 min had higher crystalline quality than the Mn-implanted GaN layers fabricated with Mn ion doses of 5 × 1015 and 2 × 1016 cm−2 followed by annealed at 900 °C for 30 and 80 min. Keywords Mn-implantation · GaN · Thermal annealing · Raman · Photoluminescence
Introduction Dilute magnetic semiconductors (DMSs) based on (In,Mn) As and (Ga,Mn)As have been much investigated because of their potential application in spintronic devices that exploits the charge and spin of electrons [1–4]. After realization of (In,Mn)As and (Ga,Mn)As, increasing effort has been devoted to (Ga,Mn)N DMSs because of two main reasons. First, GaN-based III–V semiconductors have potential applications in electronic and optoelectronic devices, such as blue-ultraviolet light-emitting diodes and laser diodes [5–7]. Second, for device applications, it is desirable to find materials that exhibit ferromagnetism at as high a temperature as possible. Although the concentration of Mn in GaMnAs has reached 10%, the Curie temperature is no higher than 150 K [8, 9]. A theoretical study [10] has shown that it could be possible for the wide band gap semiconductors GaN and ZnO to realize ferromagnetism at room temperature
or higher. Therefore, GaN layers including Mn atoms are expected to be used for novel spintronic device applications. Although some experimental studies on the magnetic characteristics of GaN-based DMSs have been reported [11–15], there are many fundamental properties of (Ga,Mn)N that are still not clear and need to be investigated, especially the magnetic ion related properties. Here, we report the effect of Mn incorporation on the structural and optical properties of GaN grown on a sapphire substrate in a plasma-enhanced molecular-beam epitaxy (PEMBE) system followed by Mn ion implantation and annealing. The magnetic properties of the Mn-implanted GaN followed after annealing will not be included in this work and published elsewhe
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