hydrogen, which bonds to the dangling bonds and can reduce the dangling bond density by several orders of magnitude. Hydrogenated amorphous silicon (a-Si:H) Amorphous silicon (a-Si) is the non-crystalline form of silicon used to create solar cells in solar panels and thin-film transistors in LCDs. Used as semiconductor material for a-Si solar cells, or thin-film silicon solar cells, it is deposited in thin films onto a variety of flexible substrates, such as glass, metal and plastic. Amorphous silicon cells generally feature low efficiency. Amorphous Hydr…

Amorphous hydrogenated silicon carbide (a-SiC x :H) could be used as a passivating layer in solar cell configuration. We have deposited a-SiC x :H by plasma enhanced CVD on polished silicon wafers. Si-rich a-SiC x :H allows to reach a surface recombination velocity of 7.5 cm.s-1. The hydrogenation of silicon surface dangling bonds and the electrical field-effect near the interface are analyzed by minority carrier lifetime and C(V) measurements and additional FTIR and XPS spectroscopy. The fixed charges within the layers are found to be amphoteric. The interface trap density increases with carb

the dangling bonds and other defects that form electronic surface states, which impair performance of the devices. Surface passivation of silicon usually Passivation, in physical chemistry and engineering, refers to coating a material so it becomes "passive", that is, less readily affected or corroded by the environment. Passivation involves creation of an outer layer of shield material that is applied as a microcoating, created by chemical reaction with the base material, or allowed to build by spontaneous oxidation in the air. As a technique, pas Passivation, in physical chemistry and engineering, refers to coating a material so it becomes "passive", that is, less readily affected or corroded by the environment. Passivation involves creation of an outer layer of shield material that is applied as a microcoating, created by chemical reaction with the base material, or allowed to build by spontaneous oxidation in the air. As a technique,…

We have experimentally demonstrated single mode amorphous silicon channel waveguides with low optical transmission loss of 2.7±0.4 dB/cm for TE mode in the 1550 nm range. This result was achieved by using hydrogen passivation of a-Si dangling bonds and a thin, low loss silicon nitride intercladding layer prepared by plasma enhanced chemical vapor deposition between the waveguide core and the oxide cladding layer. The silicon nitride intercladding layer reduces waveguide sidewall roughness scattering and preserves the hydrogen passivation.

p-type hydrogenated amorphous silicon (a-Si:H) films were prepared by the mercury photosensitized decomposition of a disilane-diborane gas mixture. With increased gaseous impurity ratio (diborane/disilane), the dark conductivity was enhanced. However, the optical band gap was reduced with increasing boron concentration as generally observed in glow discharge produced boron-doped a-Si:H films. Wide optical gap (2.0–2.5 eV) hydrogenated amorphous silicon carbide (a-SiC:H) films were also prepared by the photochemical vapor deposition technique. Acetylene and dimethylsilane were used as the carbo

Low hole mobility currently limits the efficiency of amorphous silicon photovoltaic devices. We explore three possible phenomena contributing to this low mobility: coordination defects, self-trapping ionization displacement defects, and lattice expansion allowing for hole wave-function delocalization. Through a confluence of experimental and first-principles investigations, we demonstrate the fluidity of the relative prevalence of these defects as film stress and hydrogen content are modified, and that the mobility of a film is governed by an interplay between various defect types.

Molybdenum oxide (MoO X ) combines a high work function with broadband optical transparency. Sandwiched between a hydrogenated intrinsic amorphous silicon passivation layer and a transparent conductive oxide, this material allows a highly efficient hole-selective front contact stack for crystalline silicon solar cells. However, hole extraction from the Si wafer and transport through this stack degrades upon annealing at 190 °C, which is needed to cure the screen-printed Ag metallization applied to typical Si solar cells. Here, we show that effusion of hydrogen from the adjacent layers is a lik