Ferromagnetic nanoclusters hybridized in Mn-incorporated GaInAs layers during metal–organic vapour phase epitaxial growth on InP layers under low growth temperature conditions

Abstract

We demonstrate the successful formation of ferromagnetic nanoclusters in Mn-incorporated GaInAs layers grown by metal-organic vapour phase epitaxy on InP (100) substrates under low growth temperature conditions below 450 °C. We find that MnAs nanoclusters with NiAs-type hexagonal crystallographic structures, which show ferromagnetic characteristics up to a relatively high temperature of about 305 K, are formed near the layer surfaces of Mn-incorporated GaInAs layers grown at 440 °C. After deposition of undoped InP layers on Mn-incorporated GaInAs layers, MnP nanoclusters with orthorhombic cubic crystallographic structures, in which 7% arsenic is incorporated, are formed in InP layers. The samples with MnP nanoclusters show strong ferromagnetic coupling up to about 305 K, although the Curie temperature of MnP bulk compounds is 291 K. Energy dispersive x-ray spectroscopy (EDS) indicates that Mn concentrations in InP and GaInAs layers surrounding MnP nanoclusters are almost negligible. MnAs nanoclusters are also formed in Mn-incorporated GaAs layers grown under low growth temperature conditions of 450 °C on GaAs (100) substrates. From the results of magnetic characterizations with respect to growth temperatures of the samples, we found that all the Mn-incorporated GaAs layers grown at temperatures below 450 °C showed ferromagnetic behaviour. 61.46.+w, 68.37.Lp, 75.75.+a, 81.15.Gh, [2,3] and so on (for a review, see [1,2]). Almost all of these materials have been grown by low temperature molecular beam epitaxy (LTMBE) or ion implantation of magnetic materials on semiconductors [4]. However, although metal-organic vapour phase epitaxy (MOVPE) is one of the most important and preferred technologies for the fabrication of electronic and photonic semiconductor devices, particularly in a production fashion, there are nevertheless only a few reports on MOVPE growth of III-V DMS materials and FM III-V hybrids [5 -8]. PACS:Magneto-optical devices utilizing the Faraday or Kerr effect for III-V DMS materials or FM III-V hybrids are very promising for realizing monolithic integration of magneto-optical devices such as waveguide-type optical isolators or circulators on the present III-V compound semiconductor-based photonic integrated circuits (PICs). This is because such a material system is compatible with III-V compound semiconductors such as GaAs and InP. In particular, FM III-V hybrids are more suitable because they show strong ferromagnetic coupling even above room temperature. Optical isolators are key devices in optical communication systems for 1.3 or 1.55 µm wavelength bands for reducing the external relative feedback noise in distributed feedback (DFB) lasers integrated on the PICs. Techniques for achieving direct bonding between semiconductors and magneto-optical materials have been proposed [9]. However, no successful monolithic integration of optical isolators using epitaxial growth techniques has been realized so far for the present III-V compound semiconductor-based PICs. Recently, device structures for...

Self-assembled formation of ferromagnetic MnAs nanoclusters on GaInAs/InP (1 1 1) B layers by metal-organic vapor phase epitaxy

“…Bis-(methylcyclopentadienyl) manganese ((MeCp) 2 Mn) was chosen as a manganese organometallic precursor [3]. The temperature of (MeCp) 2 Mn was controlled at 70 1C in order to increase its vapor pressure.…”

“…Major advantages of FM III-V hybrids are possible monolithic integration of nanospintronic devices on the III-V compound semiconductor-based integrated circuits (ICs) and strong ferromagnetic coupling above room temperature. We have grown FM III-V hybrids by metal-organic vapor phase epitaxy (MOVPE), in particular, using MnAs nanoclusters embedded in GaInAs/ InP (0 0 1) layers, which is suitable for highly integrated photonic ICs used in optical communication systems [2,3]. In this paper, we demonstrate the successful self-assembled formation of hexagonal ferromagnetic MnAs nanoclusters epitaxially grown on GaInAs/InP (1 1 1) B layers.…”

Magnetic domain characterizations of anisotropic-shaped MnAs nanoclusters position-controlled by selective-area metal-organic vapor phase epitaxy

“…͑CH 3 ͒ 3 Ga, ͑CH 3 ͒ 3 Al, ͑CH 3 C 5 H 4 ͒ 2 Mn and 20%-AsH 3 diluted in H 2 were used as source materials for SA-MOVPE. 17 The growth temperature, T g , and the V/Mn ratio, whose definition was given elsewhere, 10 were 800-850°C and 375-1125, respectively. MnAs NCs were formed directly on partially SiO 2 -masked GaAs ͑111͒B wafers ͑Figs.…”

Hexagonal ferromagnetic MnAs nanocluster formation on GaInAs∕InP (111)B layers by metal-organic vapor phase epitaxy

“…͑CH 3 C 5 H 4 ͒ 2 Mn was chosen as a Mn organometallic precursor. 8 After the growth of GaInAs layers on InP buffer layers, ͑CH 3 C 5 H 4 ͒ 2 Mn was introduced to the MOVPE reactor with AsH 3 . All the layers were grown on diamagnetic InP ͑111͒B wafers, and, as a reference, InP ͑001͒ substrates were used at the same growth runs.…”

“…5,6 We have pursued FM III-V hybrids, in particular, using MnAs nanoclusters ͑NCs͒ embedded in GaInAs/ InP ͑001͒ layers grown by MOVPE. 7,8 InP-related materials are more suitable for the fabrication of key devices in optical communication systems for 1.3 and 1.55 m wavelength bands. Recently, LT-MBE of III-V DMS, e.g., GaInMnAs, on InP ͑001͒ wafers has been reported, 9,10 and waveguide-type optical isolators using the magneto-optical effects of MnAs NCs have been proposed.…”