References of "Physica Status Solidi A. Applications and Materials Science"
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See detailBetter Cu(In,Ga)Se2 solar cells based on surface treated stoichiometric absorbers
Choubrac, Léo UL; Bertram, Tobias UL; Elanzeery, Hossam UL et al

in Physica Status Solidi A. Applications and Materials Science (2017), 214, No. 1

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See detailElectrodeposition of Kesterite thin films for photovoltaic applications: Quo vadis?
Colombara, Diego UL; Crossay, Alexandre UL; Vauche et al

in Physica Status Solidi A. Applications and Materials Science (2015), 212(1), 88-102

This paper aims at providing an updated overview of the main achievements in the development of solar cells based on Cu2ZnSn(S,Se)4 (CZTS(Se)) kesterite absorbers obtained by electrodeposition. Although ... [more ▼]

This paper aims at providing an updated overview of the main achievements in the development of solar cells based on Cu2ZnSn(S,Se)4 (CZTS(Se)) kesterite absorbers obtained by electrodeposition. Although undoubtedly challenging, the ultimate goal is to learn from the past works and build a solid framework for future advances in this field. What is the reason for the lower efficiency of electrodeposited CZTS(Se)-based devices (8%) compared to the world record efficiency achieved with a hydrazine-based solution approach (12.6%)? Can this gap be filled, or there are intrinsic limitations for this achievement? The review is divided into the three main electrodeposition approaches: sequential elemental layer, alloy co-deposition, and chalcogenide co-deposition. It is argued that considerable technical challenges must be overcome for the latter approach to be successfully applied. [less ▲]

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See detailEffects of a non-absorbing substrate on the magneto-optical Kerr response of plasmonic ferromagnetic nanodisks
Maccaferri, Nicolò UL; Kataja, Mikko; Bonanni, Valentina et al

in Physica Status Solidi A. Applications and Materials Science (2014), 211(5), 1067-1075

Magnetoplasmonics is an emerging field of intense research on materials combining magnetic and plasmonic functionalities. The novel optical and magneto-optical (MO) properties displayed by these materials ... [more ▼]

Magnetoplasmonics is an emerging field of intense research on materials combining magnetic and plasmonic functionalities. The novel optical and magneto-optical (MO) properties displayed by these materials could allow the design of a new class of magnetically controllable optical nano-devices. In this work, we investigate the effects of a non-absorbing (insulating) substrate on the MO activity of pure ferromagnetic disk-shaped nanostructures supporting localized plasmon resonances. We show that the red-shift of the localized plasmon resonance, related to the modification of the localization of the electromagnetic field due to the substrate, is not the only effect that the substrate has on the MO response. We demonstrate that the reflectivity of the substrate itself plays a key role in determining the MO response of the system. We discuss why it is so and provide a description of the modeling tools suitable to take into account both effects. Understanding the role of the substrate will permit a more aware design of magnetoplasmonic nanostructured devices for future biotechnological and optoelectronic applications. [GRAPHICS] Ferromagnetic nickel nanodisk in vacuum (left) and on a non-absorbing substrate (right), illuminated by linearly polarized light. The polarization of the reflected field is changed in the first case due to a combination of intrinsic magneto-optical properties and the nanoconfinement of the material. In the second case, the polarization of the reflected light is affected also by the presence of the substrate. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [less ▲]

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See detailFabrication and characterization of kesterite Cu2ZnSnS4 thin films deposited by electrostatic spray assisted vapour deposition method
Liu, J. P.; Choy, Kwang-Leong; Placidi, M. et al

in Physica Status Solidi A. Applications and Materials Science (2014)

Most of the high efficiency kesterite solar cells are fabricated by vacuum or hydrazine-based solution methods which have drawbacks, such as high cost, high toxicity or explosivity. In our contribution ... [more ▼]

Most of the high efficiency kesterite solar cells are fabricated by vacuum or hydrazine-based solution methods which have drawbacks, such as high cost, high toxicity or explosivity. In our contribution, an alternative non-vacuum and environmental friendly deposition technology called electrostatic spray assisted vapour deposition (ESAVD) has been used for the cost-effective growth of Cu2ZnSnS4 (CZTS) thin films with well controlled structure and composition. CZTS films have been characterized using a combination of XRD, XPS, SEM-EDX, AFM, and Raman spectroscopy. The results demonstrated that adherent, uniform and homogeneous CZTS films without apparent secondary phases have been produced by ESAVD. The atomic ratios measured by EDX are Cu/(Zn + Sn) = 0.88 and Zn/Sn = 1.17,which are very close with the reported high efficiency solar cells and can be finely tuned by formulating the precursor.CZTS films exhibited a typical optical band gap of 1.53 eV from UV–Vis analysis. Cu2ZnSnS4 produced by the ESAVD are being optimized towards the fabrication of high efficiency photovoltaic devices. [less ▲]

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See detailComparative study on unpassivated and passivated AlGaN/GaN HFETs and MOSHFETs
Heidelberger, G.; Bernát, J.; Gregušová, D. et al

in Physica Status Solidi A. Applications and Materials Science (2006), 203(7), 1876-1881

In this comparative study we investigate AlGaN/GaN-based unpassivated and passivated HFETs and MOSHFETs with regards to DC-, RF-, and power-performance. For optimal comparability, all devices emanate from ... [more ▼]

In this comparative study we investigate AlGaN/GaN-based unpassivated and passivated HFETs and MOSHFETs with regards to DC-, RF-, and power-performance. For optimal comparability, all devices emanate from the same wafer consisting of a SiC-substrate, a 3 μm GaN- and a 30 nm Al0.28Ga0.72N-layer. Devices are processed simultaneously to a large extend. Passivated devices are coated with a 10 nm thick SiO2-layer between the electrodes, MOSHFETs contain a 10 nm thick SiO2-layer serving as gate-insulator underneath the gate and as conventional passivation-layer between the electrodes. Unpassivated devices serve as reference. We present empirical evidence that MOSHFETs outperform both the conventional and the passivated HFETs with respect to DC-, RF-, and power-performance, and we point out the different mechanisms responsible for the behaviour of the devices. [less ▲]

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See detailInfluence of doping concentration on DC and RF performance of AlGaN/GaN HEMTs on silicon substrate
Marso, Michel UL; Javorka, P.; Dikme, Y. et al

in Physica Status Solidi A. Applications and Materials Science (2003), (1), 179-182

AlGaN/GaN HEMTs with different carrier supply layers are fabricated on Si substrate, using MOVPE growth technique. The influence of the carrier supply doping concentration on the HEMT properties is ... [more ▼]

AlGaN/GaN HEMTs with different carrier supply layers are fabricated on Si substrate, using MOVPE growth technique. The influence of the carrier supply doping concentration on the HEMT properties is investigated by Hall measurements and by electrical DC and RF characterisation of transistor devices. Hall mobility is found to decrease with increasing sheet concentration, while the gate leakage current increases. The device with the highest carrier supply doping concentration of 1019 cm–3 is provided with a GaN cap layer to reduce gate leakage. The transistors based on modulation doped layer structures show much higher DC performance than the undoped device. Best RF properties are obtained for a doping level of 5 × 1018 cm–3. High frequency measurements exhibit fT and fMAX values of 35 GHz and 37 GHz, respectively, for devices with 300 nm gate length. [less ▲]

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See detailFabrication and performance of AlGaN/GaN HEMTs on (111) Si substrates
Javorka, P.; Alam, A.; Marso, Michel UL et al

in Physica Status Solidi A. Applications and Materials Science (2002), 194(2), 472-475

In the current work the performance of AlGaN/GaN HEMTs fabricated on silicon substrates is presented. The AlGaN/GaN material structures were grown on (111) Si by MOVPE. Static I–V characteristics with a ... [more ▼]

In the current work the performance of AlGaN/GaN HEMTs fabricated on silicon substrates is presented. The AlGaN/GaN material structures were grown on (111) Si by MOVPE. Static I–V characteristics with a saturation current of 0.91 A/mm and a peak extrinsic transconductance of 122 mS/mm were measured and show minimal thermal effects. For devices with a gate length of 0.7 um and 0.5 um, a unity gain frequency of 20 GHz and 32 GHz and a maximum frequency of oscillation of 22 GHz and 27 GHz, respectively were obtained. The unity gain frequencies are the highest values reported so far on AlGaN/GaN/Si HEMTs and fully comparable to those known for devices using sapphire and SiC substrates. However, the fmax to fT ratio is only about 1, which indicates on parasitic conduction through the Si substrate under small signal conditions. It is shown that the saturation current and the transconductance decrease much less with increased temperature than known for similar devices grown on sapphire. [less ▲]

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See detailInfluence of Surface Treatments on DC-Performance of GaN-Based HFETs
Mistele, D.; Rotter, T.; Bougrioua, Z. et al

in Physica Status Solidi A. Applications and Materials Science (2002), 194(2), 452-455

This work reports on the influence of the surface and the gate length on the performance of AlGaN/GaN based Hetero Field Effect Transistors (HFETs). Differently NH4Sx treated surfaces result in variation ... [more ▼]

This work reports on the influence of the surface and the gate length on the performance of AlGaN/GaN based Hetero Field Effect Transistors (HFETs). Differently NH4Sx treated surfaces result in variation of the drain current IDmax of more then 100%. Gate recessing by photoelectrochemical treatment changes the threshold voltage Vth but affects the drain current little. Next, the reduction of the gate length increases the IDmax further by more than 60%. The IDmax values for the transistors are 350 mA mm––1 for the NH4Sx-treated, 850 mA for the untreated, and 1.43 A mm––1 for the one with a 0.2 mm gate length. The corresponding transconductances gm are 66, 150, and 280 mS mm––1, respectively. Surface analysis with Auger Electron Spectroscopy (AES) and contact characterization (TLM) reveals, that the NH4Sx treatment removes the native oxide and increases the contact resistance as well. Therefore we attribute the increase of IDmax and gm mainly to a beneficial behavior of gallium-oxide at the surface on the sheet carrier density nS of the 2DEG at the heterointerface. [less ▲]

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See detailGrowth and characterisation of AlGaN/GaN-HEMTs on silicon substrates,
Kalisch, H.; Dikme, Y.; Gerstenbrandt, G. et al

in Physica Status Solidi A. Applications and Materials Science (2002), 194(2), 464-467

In order to analyse and to compare the properties of AlGaN/GaN HEMT on silicon and on sapphire substrates, studies on both layers and device types have been performed. Besides the substantially lower ... [more ▼]

In order to analyse and to compare the properties of AlGaN/GaN HEMT on silicon and on sapphire substrates, studies on both layers and device types have been performed. Besides the substantially lower substrate costs compared to SiC, the use of silicon as substrate provides the advantage of a higher thermal conductivity compared to sapphire allowing a more efficient heat removal from the device and thus higher RF power densities. On silicon, up to 900 nm of GaN as well as HEMT structures have been deposited and characterised regarding their structural, optical and electrical properties. HEMT devices with various gate lengths were processed and measured onwafer under continuous and pulsed operation conditions. The properties of the layers and devices on silicon substrates are developing to become comparable to those based on sapphire and silicon carbide. [less ▲]

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