Amorphous silicon

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

Method of forming polycrystalline silicon layer on substrate by large area excimer laser irradiation

Abstract: A method of forming a polycrystalline silicon thin film improved in crystallinity and a channel of a transistor superior in electrical characteristics by the use of such a polycrystalline silicon thin film. An amorphous silicon layer of a thickness preferably of 30 nm to 50 nm is formed on a substrate. Next, substrate heating is performed to set the amorphous silicon layer to preferably 350° C. to 500° C., more preferably 350° C. to 450° C. Then, at least the amorphous silicon layer is irradiated with laser light of an excimer laser energy density of 100 mJ/cm2 to 500 mJ/cm2, preferably 280 mJ/cm2 to 330 mJ/cm2, and a pulse width of 80 ns to 200 ns, preferably 140 ns to 200 ns, so as to directly anneal the amorphous silicon layer and form a polycrystalline silicon thin film. The total energy of the laser used for the irradiation of excimer laser light is at least 5 J, preferably at least 10 J.

Dielectric core-shell optical antennas for strong solar absorption enhancement.

Abstract: We demonstrate a new light trapping technique that exploits dielectric core–shell optical antennas to strongly enhance solar absorption. This approach can allow the thickness of active materials in solar cells lowered by almost 1 order of magnitude without scarifying solar absorption capability. For example, it can enable a 70 nm thick hydrogenated amorphous silicon (a-Si:H) thin film to absorb 90% of incident solar radiation above the bandgap, which would otherwise require a thickness of 400 nm in typical antireflective coated thin films. This strong enhancement arises from a controlled optical antenna effect in patterned core–shell nanostructures that consist of absorbing semiconductors and nonabsorbing dielectric materials. This core–shell optical antenna benefits from a multiplication of enhancements contributed by leaky mode resonances (LMRs) in the semiconductor part and antireflection effects in the dielectric part. We investigate the fundamental mechanism for this enhancement multiplication and de...

Electron and hole drift mobility in amorphous silicon

Abstract: Electron and hole drift mobility have been measured in n‐ and p‐type amorphous Si Schottky‐barrier solar cells. At room temperature μdn= (2–5) ×10−2 cm2/V sec and μdp= (5–6) ×10−4 cm2/V sec. Both mobilities are trap controlled with ΔE=0.19 eV for electrons and ΔE=0.35 eV for holes above 250 °K and ΔE=0.16 and 0.26 eV, respectively, below 250 °K. Majority‐carrier lifetimes are estimated to be 1 μsec for electrons and 25 μsec for holes.