Amorphous silicon

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

Polysilicon thin film transistors fabricated on low temperature plastic substrates

Abstract: We present device results from polysilicon thin film transistors (TFTs) fabricated at a maximum temperature of 100 °C on polyester substrates. Critical to our success has been the development of a processing cluster tool containing chambers dedicated to laser crystallization, dopant deposition, and gate oxidation. Our TFT fabrication process integrates multiple steps in this tool, and uses the laser to crystallize deposited amorphous silicon as well as create heavily doped TFT source/drain regions. By combining laser crystallization and doping, a plasma enhanced chemical vapor deposition SiO2 layer for the gate dielectric, and postfabrication annealing at 150 °C, we have succeeded in fabricating TFTs with ION/IOFF ratios >5×105 and electron mobilities >40 cm2/V s on polyester substrates.

Experimental evidence for nanoparticle deposition in continuous argon–silane plasmas: Effects of silicon nanoparticles on film properties

Abstract: These last few years a great effort has been made to understand the mechanisms of powder formation in silane discharges. It is now well established that powders are negatively charged and thus confined in the plasma. Therefore, one does not expect powders to contribute to the deposition, unless the plasma is switched off. We present here experimental evidence for the deposition of nanoparticles, even in the case of a continuous discharge. Experimental conditions for nanoparticle formation while avoiding powder formation have been determined from light‐scattering and transmission electron microscopy measurements. Nanoparticle deposition has been studied by in situ ellipsometry in silane–argon discharges. From a comparison of the growth kinetics and the optical properties of films obtained under continuous and modulated discharges we conclude that nanoparticle deposition can take place even when the discharge is on. The implications of these discoveries on the properties of hydrogenated amorphous silicon ar...

Heterojunction silicon microwire solar cells.

Abstract: We report radial heterojunction solar cells of amorphous silicon on crystalline silicon microwires with high surface passivation. While the shortened collection path is exploited to increase the photocurrent, proper choice of the wire radius and the highly passivated surface prevent drastic decrease in the voltage due to high surface-to-volume ratio. The heterojunction is formed by depositing a ∼12–16 nm of amorphous silicon on crystalline silicon wires of radius approximately equal to minority carrier diffusion length (∼10 μm). In spite of very short carrier lifetime (<1 μs), the microwire array devices generate photocurrent of ∼30 mA/cm2, and the same time, voltages close to 600 mV are achieved, leading to efficiency in excess of 12% in extremely short carrier lifetime silicon. We also find that formation of nanocrystallites of silicon in the deposited film results in loss of the expected passivation.

Amorphous Si/Polycrystalline Si Stacked Solar Cell Having More Than 12% Conversion Efficiency

Abstract: A new type of amorphous silicon (a-Si) solar cell stacked with polycrystalline silicon (poly-c-Si) has been developed. The conversion efficiency more than 12% has been obtained with a cell structure of ITO//n-i-p a-Si//n a-Si/p poly c-Si//Al. A series of technical data on the cell fabrication and resulting photovoltaic characteristics are presented.