Janne Puustinen

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In this study, we investigate the effect of annealing and nitrogen amount on electronic transport properties in n- and p-type-doped Ga0.68In0.32NyAs1 - y/GaAs quantum well (QW) structures with y = 0%, 0.9%, 1.2%, 1.7%. The samples are thermal annealed at 700°C for 60 and 600 s, and Hall effect measurements have been performed between 10 and 300 K. Drastic(More)
In this work the photoconductivity of a p-i-n Ga<inf>0.952</inf>In<inf>0.048</inf>N<inf>0.016</inf>As<inf>0.984</inf>/GaAs multiple quantum well (MQW) structure is investigated as a function of temperature. At low temperatures step-like increases are observed in the devices I&#x2013;V characteristic when illuminated with a 950nm wavelength light. The number(More)
We demonstrate for the first time the operation of GaInNAs and GaAs n-i-p-i doping solar cells with ion-implanted selective contacts. Multiple layers of alternate doping are grown by molecular beam epitaxy to form the n-i-p-i structure. After growth, vertical selective contacts are fabricated by Mg and Si ion implantation, followed by rapid thermal(More)
UNLABELLED We report the observation of thermal annealing- and nitrogen-induced effects on electronic transport properties of as-grown and annealed n- and p-type modulation-doped Ga1 - xInxNyAs1 - y (x = 0.32, y = 0, 0.009, and 0.012) strained quantum well (QW) structures using magnetotransport measurements. Strong and well-resolved Shubnikov de Haas (SdH)(More)
The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga1 - xInxNyAs1 - y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%,(More)
We report on fabrication and performance of wafer fused, high power, passively mode-locked semiconductor disc lasers operating in 1310 nm and 1550 nm bands. These devices comprise gain mirrors based on InAlGaAs/InP multi quantum well active regions fused to AlGaAs/GaAs-based DBRs as well as wafer fused saturable absorbers of a similar design for devices(More)
We report a comparison between the high-speed gain and absorber dynamics of dilute nitride laser structures utilising GaAs or GaAsN barrier layers. The inclusion of dilute nitride barriers greatly reduces the absorber recovery time. The wafers were processed into two-section monolithic mode-locked lasers generating 2-5 ps pulses at 40 GHz.
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