Topic
Ion implantation
About: Ion implantation is a research topic. Over the lifetime, 36395 publications have been published within this topic receiving 454497 citations.
Papers published on a yearly basis
Papers
More filters
07 May 2006
TL;DR: In this article, a low energy free-carrier generation appears in nanoscale Si-layered systems, which can lead to, in suitable conditions, internal quantum efficiencies exceeding unity.
Abstract: A low energy free-carrier generation appears in nanoscale Si-layered systems. The experimental devices contain a superficial Si nanostratum (3-5 nm thick and tensile strained) formed at the SiO2/Si heterointer-face during a processing including thermal oxidation, ion implantation and suitable thermal treatment. The nanostratum is composed of transformed c-Si. The investigation in the UV range (400 nm band) has been carried out mainly by spectral response measurements. The low energy generation allows a free-carrier multiplication which can lead to, in suitable conditions, internal quantum efficiencies exceeding unity. The best test collection efficiency we have measured up to now results in 1.35 electrons per incident photon. The new mechanism can be used for the adjustment of the quantum converter to the solar spectrum thanks to the multistage conversion. At least one of the two main limitations of conventional Si-based (bulk or thin film) solar cell performance, i.e. the only one electron-hole pair generation by energetic photons can be then overcome. The thermodynamic limit of conventional photovoltaic conversion is limited at 30%, while in the case of the mechanism reported here, if can be propelled above 60%.
12 citations
01 May 2002-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, luminescence is reported for alumina and Al 2 O 3 :Cu films grown by pulsed laser deposition and is contrasted with luminecence from Cu ion implanted silica, which offers a route to monitor the state of the defects and the copper impurity ions.
Abstract: Luminescence is reported for alumina and Al 2 O 3 :Cu films grown by pulsed laser deposition and is contrasted with luminescence from Cu ion implanted silica. The implanted samples display numerous emission bands with at least two associated to charge states or the Cu ions. The relative band intensities are altered by thermal treatments. In the case of the thin films the signals are sensitive to the growth conditions and show evidence for trapped Ar nanoparticles, from argon used as a background gas during film growth. Thus in both thin film and ion implanted material the luminescence offers a route to monitor the state of the defects and the copper impurity ions.
12 citations
01 Dec 2003-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this article, single crystal n-type silicon samples were implanted at room temperature sequentially by molecular oxygen (16O2+) and nitrogen (14N2+) in different proportions to high fluence levels ranging from 5.5 to 1.8 ions cm−2 to synthesize silicon oxynitride layers.
Abstract: Single crystal n-type silicon samples were implanted at room temperature sequentially by molecular oxygen (16O2+) and nitrogen (14N2+) in different proportions to high fluence levels ranging from 5 × 1016 to 1 × 1018 ions cm−2 to synthesize silicon oxynitride layers of various compositions. Rapid thermal annealing (RTA) of some samples was carried out at different temperatures in nitrogen ambient. Fourier transform infrared (FTIR) measurements were performed on as-implanted and on annealed samples. The FTIR studies show that the structure of ion-beam synthesized oxynitride layers are strongly dependent on total ion-fluence as well as on the ratio of implanted oxygen and nitrogen. The SixOyNz structures formed at lower fluence levels are homogeneous, at intermediate fluence levels are composed of separate phases of oxide, nitride and some complexes of O, N and Si and at higher fluence levels seem to have again homogeneous silicon oxynitride complex structures (SixOyNz) due to sputter limited profile of implanted ions. RTA studies show pronounced structural changes of the ion-beam synthesized layers on heat treatment at different temperatures. The spectra of annealed samples showed shift of the peak towards higher wave number. The ESR signal of silicon samples implanted to different fluence levels exhibited an isotropic g-value of 2.0045 corresponding to D-center with line width 8 G. The spin density was found to decrease with increase in ion-fluence.
12 citations
TL;DR: In this paper, the authors simulated the crystal of GaAs by a molecular cluster and computed the electronic states of the entire system by an LCAO-MO technique (extended-Huckel theory).
Abstract: The ion implantation of oxygen in either n or p-type gallium arsenide results in the formation of a semi-insulating layer that is thermally stable. There still is no reasonable explanation for this phenomenon (except one of us has made a preliminary investigation1 ). In this paper, we simulate the crystal of GaAs by a molecular cluster. As is well known the molecular-cluster model has a shortcoming in introducing “surface states” owing to the dangling of atomic bonds on the surfaces.1 In order to suppress this effect, the dangling bonds were saturated with hydrogen atoms as proposed by Larkins.3 Therefore, in this paper the perfect crystal of GaAs was simulated by a cluster of atoms with a composition Ga4As13H36 (which corresponds to a pseudocluster Ga13As13). In the authors' opinion, this kind of treatment may cause minor changes in the positions of a few energy levels, but the general energy diagram pattern will reflect the main features of the real crystal. The electronic states of the entire system are then computed by an LCAO-MO technique (extended-Huckel theory). The substitutional oxygen OAs, the arsenic vacancy VAs, and the OAsVAs complex are treated similarly. The results of the calculation show that the substitutional oxygen (OAs) forms deep donor levels in the forbidden gap. The arsenic vacancy also forms donor levels in the forbidden gap. On the other hand, the OAsVAs complex forms deep acceptor levels in the forbidden gap. Thus we have given a reasonable model for the mechanism of the formation of an insulating layer produced by oxygen ion implantation in GaAs.
12 citations
TL;DR: In this paper, fused quartz plates have been irradiated with 100 keV C+ ions to doses up to 1×1017 ions/cm2 at room temperature and at 200 °C. The ion beam induced conductivity was monitored in situ and was found to increase by up to 8 orders of magnitude for the ion dose range studied.
Abstract: Control of the surface conductivity of insulators can be accomplished by high dose ion implantation of conductive species. The use of C+ as the implant species is particularly interesting because C can either form electrically insulating sp3 bonds or electrically conducting sp2 bonds. In the present work, fused quartz plates have been irradiated with 100 keV C+ ions to doses up to 1×1017 ions/cm2 at room temperature and at 200 °C. The ion beam induced conductivity was monitored in situ and was found to increase by up to 8 orders of magnitude for the ion dose range studied. Xe implantations over a similar range did not induce any changes in the conductivity showing that the increase in conductivity is caused by the presence of the C in the fused quartz matrix and not by damage. The conductivity, σ, is found to vary with dose D as log σ∝D−1/3 over a wide dose range, strongly supporting a hopping model for the conduction mechanism. The dependence of the conductivity on implantation temperature and on post‐im...
12 citations