Optical and Structural Properties of Mn-Implanted GaN Films

Abstract

The optical and structural properties of Mn-implanted GaN films have been investigated. The films studied were grown by metal organic chemical vapor deposition (MOCVD), with Mn implanted in 150 KeV, which can offer many distinguished advantages compared with other doping methods. A new energy band with a minimum at 2.9 eV in the reflectance spectra has been observed. The yellow band emission was greatly decreased according to the result of photoluminescence. The structure analysis revealed that the Mn doped sample has good crystal quality as the pure GaN after annealed. And further discussions on the role of Mn in GaN: Mn films have been presented.

Magnetic and optical properties of Ga1−xMnxN grown by metalorganic chemical vapour deposition

“…Following the annealing process, the dominate feature (yellow band emission) in these spectra is commonly attributed to defect centres (e.g., Ga vacancies [21]) in the GaN buffer layer and the epilayer. The decrease in intensity of the yellow band in sample C prior to annealing is attributed to the enhanced Mn incorporation; this is in good agreement with previous reports [16,17]. The transmission experiments (not shown here) revealed for the thick sample C an increase of detected light below 2.7 eV and a very weak absorption signal around 1.75 eV.…”

“…Figure 3 shows the photoluminescence (PL) behaviour of the thicker, more heavily doped sample C both before and after annealing. In this sample, the most prominent feature is the blue emission band around 3.0 eV which is also reported in both ion-implanted and MBE-grown Ga 1−x Mn x N. Transitions from conduction band electrons to Mn-related states and from shallow donor (e.g., N vacancy) to Mn acceptor states are assigned to cause these emission bands in the respective spectral range, as has been previously suggested [7,[16][17][18]. Peak energies reported for this emission band range from 2.90 eV [7] through 3.08 eV [19] at room temperature.…”

Multifunctional III-nitride dilute magnetic semiconductor epilayers and nanostructures as a future platform for spintronic devices

“…In this work, the experimental identification of the Mn ion charge state and the presence of bands in the bandgap of GaN is investigated by optical spectroscopy and electron spin paramagnetic resonance (EPR) [9,10,39,40]. Photoluminescence emission bands in the blue (~3 eV) have been observed in MOCVD-grown and Mn-implanted GaN:Mn [21,[41][42][43][44]. This provides information on defects and disorder induced by the Mn incorporation in GaN.…”

“…The band at 3.0 eV is attributed to Mnrelated or Mn-induced transitions for heavily Mn doped samples. Recently, the blue band emission was observed in MBE-grown GaMnN [49], and the appearance of these bands was assigned to transitions from conduction band electrons to Mn -related states and from shallow donor (e.g., N vacancy) to Mn acceptor states [42][43][44]50].…”

The Fermi level dependence of the optical and magnetic properties of Ga1−xMnxN grown by metal–organic chemical vapour deposition

“…Reed et al have recently shown a strong correlation between the observed magnetic signature and the position of the Fermi level in Ga 1−x Mn x N [11]. Further energy states in the GaN bandgap due to the Mn incorporation have been reported from optical spectroscopy causing photoluminescence (PL) bands predominantly in the blue, and in the yellow spectral range [4,[12][13][14][15]. However, implantation induced defect states cannot be completely ruled out as a cause for these PL bands, since most of the structures are ion-implanted Ga 1−x Mn x N epilayers.…”