Amorphous silicon

About: Amorphous silicon is a research topic. Over the lifetime, 26777 publications have been published within this topic receiving 423234 citations.

Optical modeling of a-Si:H solar cells with rough interfaces: Effect of back contact and interface roughness

Abstract: An approach to study the optical behavior of hydrogenated amorphous silicon solar cells with rough interfaces using computer modeling is presented. In this approach the descriptive haze parameters of a light scattering interface are related to the root mean square roughness of the interface. Using this approach we investigated the effect of front window contact roughness and back contact material on the optical properties of a single junction a-Si:H superstrate solar cell. The simulation results for a-Si:H solar cells with SnO2:F as a front contact and ideal Ag, ZnO/Ag, and Al/Ag as a back contact are shown. For cells with an absorber layer thickness of 150–600 nm the simulations demonstrate that the gain in photogenerated current density due to the use of a textured superstrate is around 2.3 mA cm−2 in comparison to solar cells with flat interfaces. The effect of the front and back contact roughness on the external quantum efficiency (QE) of the solar cell for different parts of the light spectrum was de...

Dramatic Reduction of Surface Recombination by in Situ Surface Passivation of Silicon Nanowires

Abstract: Nanowires have unique optical properties(1-4) and are considered as important building blocks for energy harvesting applications such as solar cells(2, 5-8) However, due to their large surface-to-volume ratios, the recombination of charge carriers through surface states reduces the carrier diffusion lengths in nanowires a few orders of magnitude,(9) often resulting in the low efficiency (a few percent or less) of nanowire-based solar cells(7, 8, 10, 11) Reducing the recombination by surface passivation is crucial for the realization of high-performance nanosized optoelectronic devices but remains largely unexplored(7, 12-14) Here we show that a thin layer of amorphous silicon (a-Si) coated on a single-crystalline silicon nanowire, forming a core–shell structure in situ in the vapor–liquid–solid process, reduces the surface recombination nearly 2 orders of magnitude Under illumination of modulated light, we measure a greater than 90-fold improvement in the photosensitivity of individual core–shell nano

Thermal conductivity and localization in glasses: Numerical study of a model of amorphous silicon.

Abstract: Numerical calculations of thermal conductivity κ(T) are reported for realistic atomic structure models of amorphous silicon with 1000 atoms and periodic boundary conditions. Using Stillinger-Weber forces, the vibrational eigenstates are computed by exact diagonalization in harmonic approximation. Only the uppermost 3% of the states are localized. The finite size of the system prevents accurate information about low-energy vibrations, but the 98% of the modes with energies above 10 meV are densely enough represented to permit a lot of information to be extracted. Each harmonic mode has an intrinsic (harmonic) diffusivity defined by the Kubo formula, which we can accurately calculate for ω>10 meV

Microstructure of plasma‐deposited a‐Si : H films

Abstract: Using transmission and scanning electron microscopy, it is shown that plasma deposition of amorphous silicon hydrogen films from silane or silane/argon mixtures proceeds via nucleation and growth of islands of average lateral dimensions ∼100 A. If these islands do not coalesce into a homogeneous film, subsequent growth produces columnar morphology with low‐density interstitial regions. There is a strong correlation between the columnar structure and the presence of nonradiative recombination centers.

Application of amorphous silicon field effect transistors in addressable liquid crystal display panels

Abstract: It is shown that thin-film field effect transistors (FETs) made from amorphous (a-) silicon deposited by the glow-discharge technique have considerable potential as switching elements in addressable liquid crystal display panels. The fabrication of the elements and their characteristics with steady and pulsed applied potentials are discussed in some detail. Two important points are stressed: (i) a-Si device arrays can be produced by well-established photolithographic techniques, and (ii) satisfactory operation at applied voltages below 15VV is possible. Small experimental 7×5 transistor panels have been investigated and it is shown that with the present design up to 250-way multiplexing could be achieved. The reproducibility of FET characteristics is good and in tests so far no change has been observed after more than 109 switching operations.