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Amorphous silicon
About: Amorphous silicon is a research topic. Over the lifetime, 26777 publications have been published within this topic receiving 423234 citations.
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TL;DR: In this article, glow discharge amorphous silicon at 4.2 K and 77 K was found to have a fatigue in luminescence, which was not recovered by infra-red illumination, but by heating the sample at higher temperatures.
82 citations
TL;DR: In this paper, a very low shot laser process was applied to thin-film transistors (TFTs) made from a new hybrid process in which amorphous silicon (a-Si) is first converted to polycrystalline silicon (poly-Si), and then improved using excimer laser annealing (laser MILC or L-MILC).
Abstract: We report results on thin-film transistors (TFTs) made from a new hybrid process in which amorphous silicon (a-Si) is first converted to polycrystalline silicon (poly-Si) using Ni-metal-induced lateral crystallization (MILC), and then improved using excimer laser annealing (laser MILC or L-MILC) With only a very low shot laser process, we demonstrate that laser annealing of MILC material can improve the electron mobility from 80 to 170 cm/sup 2//Vs, and decrease the minimum leakage current by one to two orders of magnitude at a drain bias of 5 V Similar trends occur for both p- and n-type material A shift in threshold voltage upon laser annealing indicates the existence of a net positive charge in Ni-MILC material, which is neutralised upon laser exposure The MILC material in particular exhibits a very high generation state density of /spl sim/10/sup 19/ cm/sup -3/ which is reduced by an order of magnitude in L-MILC material The gate and drain field dependences of leakage current indicate that the leakage current in MILC transistors is related to this high defect level and the abruptness of the channel/drain junction This can be improved with a lightly doped drain (LDD) implant, as in other poly-Si transistors
82 citations
TL;DR: In this article, a new type of high-efficiency solar cell has been developed by a simple production process only with electron cyclotron resonance plasma assisted chemical vapor deposition of highly conductive microcrystalline silicon carbide (μ c ‐SiC) on polycrystaline silicon (poly-Si).
Abstract: A new type of high‐efficiency solar cell has been developed by a simple production process only with electron cyclotron resonance plasma‐assisted chemical vapor deposition of highly conductive microcrystalline silicon carbide (μ c ‐SiC) on polycrystalline silicon (poly‐Si). The device consists of a p ‐type μ c ‐SiC/ n ‐type poly‐Si heterojunction where the window material is a specially made wide‐band gap and highly conductive μ c ‐SiC. At the present stage, a conversion efficiency of 15.4% with V oc=556 mV, J sc=35.7 mA/cm2, and F. F.=77.4% has been achieved. Also employing this device as a bottom cell in a four‐terminal amorphous silicon ( a ‐Si) tandem‐type solar cell, 16.8% efficiency has been obtained. A series of technical data on the fabrication technology and device performance is presented and discussed.
82 citations
TL;DR: In this article, the temperature and flux dependences of photoconductivity have been investigated for plasma-deposited hydrogenated amorphous silicon alloys produced under a variety of processing conditions.
Abstract: The temperature and flux dependences of photoconductivity have been investigated for plasma‐deposited hydrogenated amorphous silicon alloys produced under a variety of processing conditions. In undoped films, new features such as thermal quenching and supralinearity are observed. Such behavior is critically dependent on the position of the Fermi level, and is not observed in alloys doped by the addition to the plasma of PH3, B2H6, O2+N2 mixtures, or air. Interpretation of the data is based on a model of competing recombination centers.
82 citations
TL;DR: In this paper, it was shown that Er diffuses interstitially in amorphous Si, but is strongly bound at trapping centers, and that the binding enthalpy of these trapping sites causes the amorphus phase to be energetically favorable for Er, so that at low concentrations the Er is nearly completely segregated.
Abstract: Solid phase epitaxy of Er‐implanted amorphous Si results in segregation and trapping of the Er, incorporating up to 2×1020 Er/cm3 in single‐crystal Si. Segregation occurs despite an extremely low Er diffusivity in bulk amorphous Si of ≤10−17 cm2/s, and the narrow segregation spike (measured width ≊3 nm) suggests that kinetic trapping is responsible for the nonequilibrium concentrations of Er. The dependence of trapping on temperature, concentration, and impurities indicates instead that thermodynamics controls the segregation. We propose that Er, in analogy to transition metals, diffuses interstitially in amorphous Si, but is strongly bound at trapping centers. The binding enthalpy of these trapping sites causes the amorphous phase to be energetically favorable for Er, so that at low concentrations the Er is nearly completely segregated. Once the concentration of Er in the segregation spike exceeds the amorphous trap center concentration, though, more Er is trapped in the crystal. We also observe similar segregation and trapping behavior for another rare‐earth element, Pr.
82 citations