Related papers: Light-induced metastability in Cu(In,Ga)Se2 caused…
Light-induced instabilities/degradation in Cu(In,Ga)Se2 (CIGS) solar cells are a prevalent and urgent issue to resolve to improve performance, uniformity, and reliability. Here, mechanisms contributing to light-induced instabilities are…
The first-principal simulations are applied to study a photo-induced metastability in amorphous selenium (a-Se) and the contribution of the valence-alteration pair (VAP) defects in this process. The VAP defect is confirmed to be the…
Cu(In,Ga)Se2 based solar cells exceed power conversion efficiencies of 23 %. Yet, the fill factor of these solar cells, with best values around 80 %, is relatively low (Si reaches 84.9%) mostly due to diode factors greater than one.…
Using first-principles electronic structure calculations we identify the anion vacancies in II-VI and chalcopyrite Cu-III-VI2 semiconductors as a class of intrinsic defects that can exhibit metastable behavior. Specifically, we predict…
Electronic structure calculations within screened-exchange hybrid density functional theory show that Cu(In,Ga) antisites in both CuInSe2 and CuGaSe2 are localized hole traps, which can be attributed to the experimentally observed N2 level.…
Beta-Ga2O3 is an ultra-wide bandgap semiconductor with emerging applications in power electronics. The introduction of acceptor dopants yields semi-insulating substrates necessary for thin-film devices. In the present work, exposure of…
The dynamic interplay between light and electric field control of charge states lies at the heart of developing multifunctional optoelectronic devices. While persistent photoconductivity (PPC) and gate-voltage (VG)-induced electron trapping…
We show that optically pumped semiconductors can exhibit superconductivity. We illustrate this phenomenon in the case of a two-band semiconductor tunnel-coupled to broad-band reservoirs and driven by a continuous wave laser. More…
Reducing the thickness of Cu(In,Ga)Se2 solar cells is a key objective in order to reduce production cost and to improve sustainability. The major challenge for sub-micron Cu(In,Ga)Se2 cells is the recombination at the backside. In standard…
High-resolution angle-resolved photoemission experiments reveal subtle modifications of the surface electronic structure of VSe2. Most remarkably, we show that superconductivity can be induced in VSe2 by the right selection of substrate and…
Complex materials encompassing different phases of matter can display new photoinduced metastable states differing from those attainable under equilibrium conditions. These states can be realized when energy is injected in the material…
The influence of the Hall voltage on the photoluminescence of a dense hydrodynamic electron-hole plasma laser generated in a mesoscopic n-doped GaAs channel under intense laser excitation is studied. Laser excitation induces an interband…
We report a persistent increase or decrease in the two-dimensional electron density of AlAs or GaAs quantum wells flanked by AlGaAs barriers, brought about by illuminating the samples at T ~ 4 K while simultaneously applying a voltage bias…
Large and persistent photoconductivity (LPPC) in semiconductors is due to the trapping of photo-generated minority carriers at crystal defects. Theory has suggested that anion vacancies in II-VI semiconductors are responsible for LPPC due…
Vertical and lateral heterostructures of van der Waals materials provide tremendous flexibility for band structure engineering. Since electronic bands are sensitively affected by defects, strain, and interlayer coupling, the edge and…
We study theoretically transverse photoconductivity induced by circularly polarized radiation, i.e. the photovoltaic Hall effect, and linearly polarized radiation causing intraband optical transitions in two-dimensional electron gas (2DEG).…
Understanding defects in atomically thin van der Waals (vdW) semiconductors is essential for advancing their use in next-generation optoelectronic and photovoltaic devices. Here, we apply a combination of various impedance spectroscopy…
Sulphurization processes in Cu(In,Ga)Se$_2$ thin-film solar cells has been intensively studied in the last decade as a viable alternative to the existing Ga-grading. The main advantage of using S grading is that by substituting Se with S we…
The luminecsence of ZnSCdS-Cu phosphors of various CdS consentration (0-40%) is under investigation. The luminescence was exited by hydrogen atoms during adsorbtion of thermal energy during adsorbtion and impact recombination-heterogeneous…
Van der Waals (vdW) heterojunctions, based on two-dimensional (2D) materials, show great potential for the development of eco-friendly and high-efficiency nano-devices. Considerable research has been performed and has reported valuable…