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The authors show that the ordered three-dimensional arrays of quantum dots, i.e., quantum dot supracrystals, can be used to implement the intermediate-band solar cell with the efficiency exceeding the Shockley-Queisser limit for a single junction cell. The strong electron wave function overlap resulting in minibands formation allows one to tune the band structure and enhance the light absorption and carrier transport. A first-principles semianalytical approach was used to determine the optimum dimensions of the quantum dots and the interdot spacing to achieve a maximum efficiency in the InAs 0.9 N 0.1 / GaAs 0.98 Sb 0.02 quantum dot supracrystal photovoltaic cells.

Proton radiation damage is an important failure mechanism for electronic devices in near-Earth orbits, deep space and high energy physics facilities [1][2][3][4] . Protons can cause ionizing damage and atomic displacements, resulting in device degradation and malfunction [5][6][7][8][9][10] . Shielding of electronics increases the weight and cost of the systems but does not eliminate destructive single events produced by energetic protons 8,10 . Modern electronics based on semiconductors -even those specially designed for radiation hardness -remain highly susceptible to proton damage. Here we demonstrate that room temperature (RT) charge-density-wave (CDW) devices with quasi-two-dimensional (2D) 1T-TaS2 channels show remarkable immunity to bombardment with 1.8 MeV protons to a fluence of at least 10 14 H + cm -2 . Current-2 | P a g e voltage I-V characteristics of these 2D CDW devices do not change as a result of proton irradiation, in striking contrast to most conventional semiconductor devices or other 2D devices. Only negligible changes are found in the low-frequency noise spectra. The radiation immunity of these "all-metallic" CDW devices can be attributed to their two-terminal design, quasi-2D nature of the active channel, and high concentration of charge carriers in the utilized CDW phases. Such devices, capable of operating over a wide temperature range, can constitute a crucial segment of future electronics for space, particle accelerator and other radiation environments. | P a g eThe future of human and unmanned space exploration depends crucially on the development of new electronic technologies that are immune to space radiation, which consists primarily of protons, electrons, and cosmic rays 1-4 . The penetrating energetic radiation of deep space produces negative impacts on not only biological entities but also the electronic systems of space vehicles. Electronics capable of operating in highradiation environments are also needed for monitoring nuclear materials, medical diagnostics, radiation treatments, nuclear reactors and particle accelerators 5-12 .Shielding of electronic systems in space is limited to lower-energy electrons and protons.High-energy proton irradiation causes ionizing damage by generating excess charges at the interface regions in the complementary metal-oxide-semiconductor (CMOS) transistors and other typical microelectronic devices and integrated circuits [8][9][10][11][12][13][14] . This type of damage results in the changes in the threshold voltages and source-drain currents, potentially leading to device or system failure. Protons also can induce displacement, which typically leads to the formation of point defects in semiconductors. These are electronic trapping states that often reveal themselves by increases in low-frequency noise (LFN) 15,16 Noise increases beyond system tolerance limits is therefore an additional challenge to electronics in high-radiation environments. Shielding, the use of conventional radiation-hardened technologies and backup devices, increases system...

The Multiquadric Radial Basis Function (MQ) Method is a meshless collocation method with global basis functions. It is known to have exponentional convergence for interpolation problems. We descretize nonlinear elliptic PDEs by the MQ method. This results in modest size systems of nonlinear algebraic equations which can be efficiently continued by standard continuation software such as auto and content. Examples are given of detection of bifurcations in 1D and 2D PDEs. These examples show high accuracy with small number of unknowns, as compared with known results from the literature.

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