Abstract The outermost edges of some supernova remnants are marked by filaments pure Balmer line emission produced nonradiative shock fronts. H α profiles these provide the speed and electron–proton temperature ratio in shock. We have used Hectochelle multiobject spectrograph on MMT telescope to observe nine positions along eastern Cygnus Loop, thereby extending studies Medina et al. lower spee...

Inverted perovskite solar cells (inverted-PSCs) have exhibited advantages of longer stability, less hysteresis, and lower fabrication temperature when compared to their regular counterparts, which are important for industry commercialization. Because the great efforts that been conducted in past several years, obtained efficiency inverted-PSCs has almost caught up with ones, 25.0% versus 25.7%....

Fabricating a dense and crystalline SnO2 film has been an important step for efficient SnO2-based perovskite solar cells (PSCs). Herein, wide bandgap material, HfO2, was deposited on the surface of FTO to facilitate formation film. It found that HfO2 modification could significantly improve crystallization upper passivate trap states within layer. Moreover, high conduction band level can block ...

Optoelectronic devices based on two-dimensional (2D) materials have shown tremendous promise over the past few years; however, there are still numerous challenges that need to be overcome to enable their application in devices. These include improving their poor photoluminescence (PL) quantum yield (QY) as well as better understanding of exciton-based recombination kinetics. Recently, we develo...

We report on the lasing characteristics of threeand five-stack InAs/GaAs quantum dot QD lasers grown by metal organic chemical vapor deposition. By increasing the number of stacked dot layers to 5, lasing was achieved from the ground state at 1135 nm for device lengths as short as 1.5 mm no reflectivity coatings . The unamplified spontaneous emission and Z ratio as a function of injection curre...

III-V semiconductor nanowires (NWs) such as GaAs NWs form an interesting artificial materials system promising for applications in advanced optoelectronic and photonic devices, thanks to the advantages offered by the 1D architecture and the possibility to combine it with the main-stream silicon technology. Alloying of GaAs with nitrogen can further enhance performance and extend device function...

Improvement in the optoelectronic performance of halide perovskite semiconductors requires identification and suppression nonradiative carrier trapping processes. The iodine interstitial has been established as a deep level defect implicated an active recombination center. We analyze quantum mechanics trapping. Fast irreversible electron capture by neutral is found. effective Huang–Rhys factor ...

Colloidal semiconductor quantum wells, also commonly known as nanoplatelets (NPLs), have arisen among the most promising materials for light generation and harvesting applications. Recently, NPLs have been found to assemble in stacks. However, their emerging characteristics essential to these applications have not been previously controlled or understood. In this report, we systematically inves...

In this work we have experimentally studied several aspects of two Coulomb processes that change the number of electrons and holes in colloidal semiconductor nanocrystals (NCs). Carrier Multiplication (CM) is the production of additional electron-hole pairs by collision of a highly excited carrier with valence electrons. Efficient CM would improve the performance of solar energy conversion devi...

We have examined the influence of strain relaxation on the excitonic recombination and diffusion in In0.2Ga0.8As/AlxGa12xAs quantum-well ~QW! samples designed for high-electron-mobility transistors, using spectrally and spatially resolved polarized cathodoluminescence ~CL!. Six molecular-beam epitaxial grown samples, with varying channel thicknesses ranging from 75 to 300 Å, were examined at va...