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Articles you may be interested inEffects of a nearby Mn delta layer on the optical properties of an InGaAs/GaAs quantum well Magnetism in a Mn modulation-doped InAs/InGaAs heterostructure with a two-dimensional hole system J. Appl. Phys. 107, 093711 (2010); 10.1063/1.3388303 Linear collapse of the depolarization shift in very dilute two-dimensional hole gases

We investigated Pb x Eu 1−x Te films with x ഛ 0.2 by magneto-optical measurements. For x ϳ 0.01, the optical emission is similar to high quality EuTe films with two narrow lines attributed to excitonic recombinations associated with magnetic polarons. For increasing x, the emission becomes dominated by a broader lower energy band, which is very efficient as compared to the binary emission. The magneto-optical properties of the ternary films show various similarities with EuTe results, such as quenchings at similar temperatures and magnetic fields. Most remarkably, they also present a giant effective g-factor that makes this material a strong candidate for spintronic applications. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2961018͔EuT is a magnetic semiconductor belonging to the europium chalcogenides family that has been extensively investigated since the 1960s.1 At room temperature EuTe is paramagnetic, while below 10 K, it becomes antiferromagnetic ordered due to the exchange interaction between the magnetic moments of the Eu 2+ ions with half-filled 4f levels. EuTe has band gap energy of 2.25 eV at 10 K.2 Early studies of EuTe samples grown by traditional methods only presented a broad emission band at relatively low energy ͑ϳ1.5 eV͒.3 More recently, Heiss et al. [4][5][6] observed two additional narrow emission lines at higher energies on high quality EuTe epitaxial layers. The lines labeled MX 1 ͑1.92 eV͒ and MX 2 ͑1.88 eV͒ were attributed to excitonic recombinations associated with magnetic polarons ͑MPs͒.The ternary compound Pb x Eu 1−x Te is miscible over the whole alloy range. Its band gap energy can thus be varied in a rather wide range between the band gap energies of the binary semiconductors: 0.30 eV ͑PbTe͒ and 2.25 eV ͑EuTe͒ at 10 K. 7 Much attention has been devoted to ternary compounds with high Pb contents due to their applications for far-infrared devices. 8 Few works have been focused, however, on the low Pb limit despite its potential for spintronic devices. In this work we investigate the magneto-optical properties of Pb x Eu 1−x Te alloys with x ഛ 0.20. The films present a very efficient optical emission band with magnetooptical properties that are quite similar to high quality EuTe layers, whereas its peak can be varied between ϳ1.74 and ϳ1.92 eV. We present the results of photoluminescence ͑PL͒ measurements as a function of temperature and applied magnetic field. Based on those results, we discuss the origin of the optical emission that dominates the PL spectra from the low Pb content alloys.The samples were grown by molecular beam epitaxy in a RIBER 32P system with Eu, Te, PbTe, and BaF 2 sources. Freshly cleaved BaF 2 ͑111͒ substrates were used. The substrates were heated up to 150°C for 15 min in the preparation chamber and to 360°C for 30 min in the main growth chamber. Two different substrate temperatures were used, 145 and 175°C. Pb x Eu 1−x Te films were usually covered with a BaF 2 layer to prevent oxidation. The film growth rate was ϳ1.5 Å / s in all cases, as estimate...

We have investigated the evolution in the heteroepitaxy of InP on InGaP/GaAs (0 0 1) layers from the initial formation of a strained wetting layer (WL) up to the development of quantum dots. Atomic force microscopy and RHEED as well as continuous and time-resolved photoluminescence measurements provide evidence of four main stages for InP growth evolution. Our results indicate that the InP dot formation occurs according to the Stranski–Krastanov growth mode coupled to a WL erosion mechanism driven by the spatially variable strain field present in the WL. Moreover, the correlation of morphological and optical data indicates the stability of dot shapes and interfaces in this system.