V.-M. Korpijärvi
Tampere University of Technology
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Featured researches published by V.-M. Korpijärvi.
Applied Physics Letters | 2008
J. Pakarinen; C.S. Peng; Janne Puustinen; P. Laukkanen; V.-M. Korpijärvi; A. Tukiainen; M. Pessa
The effects of thermal annealing on GaInAs∕GaAs and GaInAsN∕GaAs quantum wells, grown by molecular beam epitaxy, were investigated. Optical and structural properties were examined upon annealing when the samples had a 200nm thick SiO2 cap layer, or were placed in a so-called GaAs box or were left uncapped. The GaAs box gave rise to the strongest photoluminescence without significant blueshift or structural changes at moderate annealing temperature. Capping with SiO2 impaired the samples and caused a more pronounced blueshift for the GaInAs quantum wells than for the GaInAsN ones. These results consolidate our understanding of the blueshift mechanisms.
Journal of Applied Physics | 2012
V.-M. Korpijärvi; Arto Aho; P. Laukkanen; A. Tukiainen; A. Laakso; M. Tuominen; Mircea Guina
GaInNAs has an important impact on developing GaAs-based optoelectronics and multijunction solar cells, but the complex nature of the nitrogen incorporation into GaInAs is still not fully understood. By combining x-ray diffraction, photoluminescence, reflection high-energy electron diffraction, and photoelectron spectroscopy measurements, we show that nitrogen incorporation is enhanced with increasing growth temperature in the range of 300–450 °C. We study the growth front and show that the surface reconstruction is (1 × 3) regardless of growth temperature in this range. The enhanced nitrogen incorporation can be modeled as a thermally activated process with activation energy of about 0.1 eV.
Journal of Applied Physics | 2012
R. Kudrawiec; M. Syperek; M. Latkowska; J. Misiewicz; V.-M. Korpijärvi; P. Laukkanen; J. Pakarinen; M. Dumitrescu; Mircea Guina; M. Pessa
The influence of non-radiative recombination on the photoluminescence decay time (τPL) has been studied for GaInNAs/GaAs quantum wells with Ga- and In-rich environments of N atoms. At low temperatures, this influence is suppressed, due to the carrier localization phenomenon, which leads to a spectral dispersion of τPL. For investigated samples, this dispersion has been found to be in the range of ~0.2–2.0 ns. With the temperature increase, the free exciton emission starts to dominate instead of the localized exciton emission and the dispersion of τPL disappears. The dynamic of free exciton recombination is strongly influenced by the non-radiative recombination, which varies between samples, due to different concentration of non-radiative centers. The study of influence of non-radiative recombination on τPL has been performed at 180 K, since this temperature is high enough to eliminate the localized emission and activate non-radiative recombination and low enough to observe excitonic emission without stron...
Applied Physics Letters | 2008
J. Pakarinen; C.S. Peng; Ville Polojärvi; A. Tukiainen; V.-M. Korpijärvi; Janne Puustinen; M. Pessa; P. Laukkanen; J. Likonen; Eero Arola
The authors report on an interesting observation regarding thermal annealing of a beryllium-doped Ga0.65In0.35As0.99N0.01/GaAs quantum well (QW) grown by molecular beam epitaxy. A QW doped at 6×1019 cm−3 exhibited superior thermal properties and about six times larger photoluminescence than an undoped QW of the same structure. X-ray diffraction and secondary ion mass spectrometry provided evidence that beryllium suppressed indium diffusion and stabilized (metastable) dilute nitride heterostructure upon annealing.
Applied Physics Letters | 2015
Sami S Alharthi; Antonio Hurtado; V.-M. Korpijärvi; Mircea Guina; Ian D. Henning; M.J. Adams
We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in future optical systems.
Journal of Applied Physics | 2014
Arto Aho; V.-M. Korpijärvi; A. Tukiainen; Janne Puustinen; Mircea Guina
We present a Maxwell-Boltzmann electron energy distribution based model for the incorporation rate of nitrogen into GaInNAs grown by molecular beam epitaxy (MBE) using a radio frequency plasma source. Nitrogen concentration is predicted as a function of radio-frequency system primary resistance, N flow, and RF power, and group III growth rate. The semi-empirical model is shown to be repeatable with a maximum error of 6%. The model was validated for two different MBE systems by growing GaInNAs on GaAs(100) with variable nitrogen composition of 0%–6%.
Applied Physics Letters | 2014
Sami S Alharthi; Antonio Hurtado; R. K. Al Seyab; V.-M. Korpijärvi; Mircea Guina; Ian D. Henning; M.J. Adams
We experimentally demonstrate the control of the light polarization emitted by a 1310 nm dilute nitride spin-Vertical Cavity Surface Emitting Laser (VCSEL) at room temperature. This is achieved by means of a combination of polarized optical pumping and polarized optical injection. Without external injection, the polarization of the optical pump controls that of the spin-VCSEL. However, the addition of the externally injected signal polarized with either left- (LCP) or right-circular polarization (RCP) is able to control the polarization of the spin-VCSEL switching it at will to left- or right-circular polarization. A numerical model has been developed showing a very high degree of agreement with the experimental findings.
Applied Physics Letters | 2009
R. Kudrawiec; V.-M. Korpijärvi; P. Poloczek; J. Misiewicz; P. Laukkanen; J. Pakarinen; M. Dumitrescu; Mircea Guina; M. Pessa
The energy fine structure, corresponding to different nitrogen nearest-neighbor environments, was observed in contactless electroreflectance (CER) spectra of as-grown GaInNAs quantum wells (QWs) obtained at various As/III pressure ratios. In the spectral range of the fundamental transition, two CER resonances were detected for samples grown at low As pressures whereas only one CER resonance was observed for samples obtained at higher As pressures. This resonance corresponds to the most favorable nitrogen nearest-neighbor environment in terms of the total crystal energy. It means that the nitrogen nearest-neighbor environment in GaInNAs QWs can be controlled in molecular beam epitaxy process by As/III pressure ratio.
Proceedings of SPIE | 2012
Tomi Leinonen; V.-M. Korpijärvi; Antti Härkönen; Mircea Guina
We review recent results concerning the development of dilute nitride based semiconductor disk lasers. We have demonstrated over 7.4 W of output power at the second harmonic wavelength (around 590 nm) using a β-BBO crystal. Over 10 W has been demonstrated at ~1.2 μm, and multi-watt output power has been achieved at 589 nm with narrow linewidth (δν < 20 MHz).
Proceedings of SPIE | 2010
Tomi Leinonen; V.-M. Korpijärvi; Janne Puustinen; Antti Härkönen; Mircea Guina; M. Pessa
We report a GaInNAs/GaAs-based disk laser producing 7 W output power at 1180 nm wavelength at a temperature of 15 °C. The laser generated more than 5 W of output power when it was forced to operate with a narrow spectrum at 1178 nm. The gain mirror was grown using a molecular beam epitaxy reactor and it comprised 10 GaInNAs QWs and a 25.5- pair GaAs/AlAs distributed Bragg reflector.