For a model system consisting of ferromagnetic layer coupled to diluted, antiferromagnetic extensive Monte Carlo simulations are performed. Exchange bias is observed as result domain state in the which develops during field cooling, carrying an irreversible state's magnetization. In agreement with recent experimental observations on Co/CoO bilayers strong dependence exchange dilution antiferromagnet found and it shown that variety typical effects associated bias, such positive temperature,...

The exchange bias coupling at ferromagnetic/antiferromagnetic interfaces in epitaxially grown Co/CoO layers can intentionally be increased by a factor of up to 3 if the antiferromagnetic CoO layer is diluted nonmagnetic defects its volume part away from interface. Monte Carlo simulations simple model ferromagnetic on antiferromagnet show and explain qualitatively dilution temperature dependence. These investigations reveal that diluting leads formation domains, which cause control bias.

Abstract Chalcopyrite-based solar cells have reached an efficiency of 23.35%, yet further improvements been challenging. Here we present a 23.64% certified for (Ag,Cu)(In,Ga)Se 2 cell, achieved through the implementation series strategies. We introduce relatively high amount silver ([Ag]/([Ag] + [Cu]) = 0.19) into absorber and implement ‘hockey stick’-like gallium profile with concentration Ga close to molybdenum back contact lower, constant in region closer CdS buffer layer. This kind...

The exchange bias coupling at ferro-/antiferromagnetic interfaces of epitaxially grown Co/CoO bilayers can be intentionally enhanced and controlled by diluting the antiferromagnetic CoO layer, i.e., introducing (i) nonmagnetic substitutions $({\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Mg}}_{x}\mathrm{O})$ or (ii) Co deficiencies $({\mathrm{Co}}_{1\ensuremath{-}y}\mathrm{O}).$ All intentional cations defects were placed away from interface throughout whole volume part layer. This way roughness...

We report on the growth, structural as well magnetic characterization of (Ga,Mn)N epitaxial layers grown directly 4H–SiC(0001) by reactive molecular-beam epitaxy. focus two under identical conditions except for Mn/Ga flux ratio. Structural reveals that sample with lower Mn content is a uniform alloy, while in layer higher content, Mn-rich clusters are found to be embedded alloy matrix. Although behavior both samples similar at low temperatures, showing antiferromagnetic characteristics...

Cu2ZnSnS4 (CZTS) solar cells typically include a CdS buffer layer in between the CZTS and ZnO front contact. For sulfide CZTS, with bandgap around 1.5 eV, band alignment is not ideal (“cliff-like”), which enhances interface recombination. In this work, we show how Zn1−xSnxOy (ZTO) can replace CdS, resulting improved open circuit voltages (Voc) for devices. The ZTO deposited by atomic deposition (ALD), process previously developed Cu(In,Ga)Se2 cells. By varying ALD temperature, position of...

Abstract Tandem solar cell structures require a high‐performance wide band gap absorber as top cell. A possible candidate is CuGaSe 2 , with fundamental of 1.7 eV. However, significant open‐circuit voltage deficit often reported for chalcopyrite cells like . In this paper, we show that the can be drastically improved in p‐Cu(In,Ga)Se and p‐CuGaSe devices by improving conduction alignment to n‐type buffer layer. This accomplished using Zn 1− x Sn O y grown atomic layer deposition, case, level...

We present a systematic study of growth, structural, and magnetic characterization $\mathrm{GaN}:\mathrm{Gd}$ layers grown directly on 6H-SiC(0001) substrates by reactive molecular-beam epitaxy with Gd concentration ranging from $7\ifmmode\times\else\texttimes\fi{}{10}^{15}$ to $2\ifmmode\times\else\texttimes\fi{}{10}^{19}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$. The structural properties these are found be identical those undoped GaN layers. However, the reveals an...

Thin film Cu(In,Ga)Se2 solar cells with ALD-deposited Zn1–xSnxOy buffer layers are fabricated and the cell properties investigated for varying ALD deposition temperatures in range from 90 °C up to 180 °C. It is found that a process window exists between 105 135 °C, where high efficiency can be achieved. At lower performance mainly limited by low fill factor at higher open circuit voltage. Numerical simulations electrical characterization used relate changes as function of temperature...

Abstract This contribution concerns the effect of Ag content in wide‐gap w Cu 1‐ In x Ga Se 2 (ACIGS) absorber films and its impact on solar cell performance. First‐principles calculations are conducted, predicting trends band gap energy ( E g ) structure across entire compositional range ). It is revealed that a detrimental negative conduction offset (CBO) with CdS buffer can be avoided for all possible values = 1.0–1.8 eV) by adjusting alloying level. opens new path to reduce interface...

Abstract Hydrogen‐doped In 2 O 3 (IOH) films are used as a transparent back contact in bifacial Cu(In,Ga)Se (CIGS) solar cells. The effect of the IOH thickness and impact sodium incorporation technique on photovoltaic parameters studied, clear correlations observed. It is shown that loss short circuit current density ( J SC ) major limitation at side illumination. introduction thin Al layer top significantly increases collection efficiency (ϕ(x)) for electrons generated close to contact....

This contribution studies the effect of ordered vacancy compounds (OVCs) on minority carrier collection in wide‐gap (Ag,Cu)(In,Ga)Se 2 (ACIGS) solar cells. For this purpose, three samples with different ([Ag]+[Cu])/([In]+[Ga]) (I/III) values were processed: 1) a very off‐stoichiometric absorber (I/III = 0.31), consisting isolated chalcopyrite patches embedded major OVC bulk phase, 2) moderately 0.77) at front and back interfaces 3) close‐stoichiometric 0.94) only few, patches. each these...

Kesterite Cu2ZnSnS4 (CZTS), having only earth-abundant elements, is a promising solar cell material. Nevertheless, the impact of SnS secondary phase, which often forms alongside CZTS synthesis at high annealing temperature, on cells poorly studied. We confirm, by means X-ray diffraction, Raman scattering, and energy dispersive spectroscopy mapping, that this phase tends to segregate both surface back side annealed films with Cu-poor Zn-rich composition. Using electron beam-induced current...

Herein, we prove that (Ag,Cu)(In,Ga)Se₂ alloy system has a wide miscibility gap, which can induce compositional grading and cause phase separation in thin-film solar absorbers.

This contribution evaluates the effect of absorber off‐stoichiometry in wide‐gap (Ag,Cu)(In,Ga)Se 2 (ACIGS) solar cells. It is found that ACIGS films show an increased tendency to form ordered vacancy compounds (OVCs) with increasing Ga and Ag contents. Very little tolerance detected for compositions giving desired properties 1) optimum bandgap ( E G ) a top cell tandem devices = 1.6–1.7 eV) at same time 2) favorable band alignment CdS buffer layer. Herein, massive formation either In‐ or...

Silver alloying of Cu(In,Ga)Se2 absorbers for thin film photovoltaics offers improvements in open-circuit voltage, especially when combined with optimal alkali-treatments and certain Ga concentrations. The relationship between alkali distribution the absorber Ag is investigated here, combining experimental theoretical studies. Atom probe tomography analysis implemented to quantify local composition grain interiors at boundaries. Na concentration bulk increases up ∼60 ppm [Ag]/([Ag] + [Cu]) =...

The compound AgGaSe2 has received limited attention as a potential wide gap solar cell material for tandem applications, despite its suitable band gap. This study aims to investigate the of this by deposition thin films co-evaporation and production devices. Since very low tolerance off-stoichiometry, reference materials possible secondary phases in Ag2Se–Ga2Se3 system were also produced. Based on these samples, it was concluded that X-ray diffraction is suited distinguish system. An attempt...

This contribution studies the potential of an RbF postdeposition treatment (RbF‐PDT) wide‐gap (Ag,Cu)(In,Ga)Se 2 (ACIGS) absorbers to improve corresponding solar cell performance. While a higher open‐circuit voltage ( V OC ) and short‐circuit current density are achieved, lower fill factor (FF) is observed for most devices subjected RbF‐PDT. However, drop in FF can be avoided some close‐stoichiometric samples, leading maximum efficiencies beyond 16% (without antireflection coating) at...

This work studies the thickness effect of atomic‐layer‐deposited AlO x films, acting as back contact passivation layers in bifacial, wide‐bandgap ( E G = 1.4–1.5 eV) (Ag,Cu)(In,Ga)Se 2 (ACIGS) solar cells with In O 3 :W transparent rear electrodes. For each tested (1.0, 2.0, and 3.5 nm), several absorber‐deposition runs, varying ACIGS thicknesses, were conducted. It is found that a nm‐thick layer results strongly impeded hole extraction thus, severe losses short‐circuit current. As...

In this work, rear-contact passivated Cu(In,Ga)Se2 (CIGS) solar cells were fabricated without any intentional contact openings between the CIGS and Mo layers. The investigated samples either Na free or one of two supply methods was used, i) a NaF precursor on top Al2O3 rear passivation layer ii) an in situ post-deposition treatment with after co-evaporation layer. thickness ALD-Al2O3 also varied order to find optimal combination thickness. Our results from electrical characterization show...