Dislocation Photoluminescence Research Articles

On the structure and photoluminescence of dislocations in silicon

This paper presents a comparative analysis of the structure and photoluminescence (PL) of Si containing dislocations introduced by thermal shock or ion implantation. To study the structure of dislocation cores and their interaction with point defects, we used a high-resolution transmission mode during in situ electron irradiation in the JEM4000EX operating at 400 kV. An appropriate PL spectrum was obtained on dislocated Si after electron irradiation by an external pulse gun operating at 350 kV. This resulted only in an increase in the D2 line intensity that correlated with the formation of metastable interstitial defects on {001}, {111}, and {113} planes near various dislocation cores during in situ electron irradiation, regardless of their types. However, the D1 line relates to a core structure of a shuffle Lomer dislocation consisting of 5/7 atomic rings, which occurs when two shuffle 60° dislocations (so-called S1 type [Pizzagalli et al., Phys. Rev. Lett. 103, 065505 (2009)]) combine with each other in intersecting {111} planes in plastically deformed Si or when an extrinsic Frank partial dislocation transforms into a perfect one in an ion-implanted layer.

Effect of ion doping on the dislocation-related photoluminescence in Si+-implanted silicon

The study is concerned with the effect of the additional implantation of Si samples with C+, O+, B+, P+, and Ge+ impurity ions followed by annealing at 800°C on the behavior of the dislocation photoluminescence line D1, induced in the samples by implantation with Si+ ions at a stabilized temperature followed by annealing in an oxidizing Cl-containing atmosphere. It is established that the intensity of the D1 line strongly depends on the type of incorporated atoms and the dose of additional implantation. An increase in the D1 line intensity is observed upon implantation with oxygen and boron; at the same time, in other cases, the D1 luminescence line is found to be quenched. The mechanisms of such behavior, specifically, the role of oxygen and its interaction with implanted impurities are discussed.

Dislocation photoluminescence in plastically deformed germanium

Dislocation photoluminescence in plastically deformed germanium

Dislocation photoluminescence in plastically deformed germanium

Abstract Dislocation photoluminescence ( PL ) was measured at 4.2 K in p-type germanium single crystals (acceptor concentration N a ∼10 14 cm −3 and density of as-grown dislocations N D ∼10 cm −2 ) deformed at temperatures 450 and 500 °C. The effect of isochronal heating of deformed samples on the spectral distribution of the recombination radiation due to regular segments of dissociated 60° dislocations of “relaxed” morphology was studied over the range from 130 to 700 °C. The substantial redistribution of the PL intensity after the 500 °C heating of deformed samples correlates with a decrease of a major portion of deformation-induced point defects ( PDs ). This suggests that the PDs annealing is accompanied by gathering of impurities near 60° dislocation cores and changing of the radiation energy of regular segments of dissociated 60° dislocations.

Dislocation Photoluminescence in Silicon and Germanium

Dislocation photoluminescence (DPL) is studied at 4.2K in plastically deformed germanium single crystals containing predominantly 60fl dislocations of “relaxed” morphology. The DPL spectra were deconvolved into Gaussian (Gm) lines of two groups over the range 0.5-0.6 eV. One of these lines corresponds to the radiation of 60fl dislocations with the equilibrium stacking fault width F0. To clarify the origin of the other Gm lines, the effect of both the dislocation density ND, ranging from106 to 109 cm-2, and the annealing at temperatures above 600flC on the intensity of Gm lines was investigated. The origin of different lines in the DPL spectra of germanium and silicon is discussed.

Peculiarities of dislocation photoluminescence in germanium with quasi‐equilibrium dislocation structure

AbstractThe dislocation photoluminescence (DPL) at 4.2 K was studied in germanium (Ge) single crystals of n‐ and p‐type with quasi‐equilibrium structure of 60° dislocations. The DPL spectra for different samples were decomposed on Gaussian lines (Gm‐lines) over the range 0.47‐0.58 eV characterized by practically the same peak energies Em and the widths under 15 meV. The G‐lines with Em ≤ 0.55 eV were ascribed to the radiation of regular segments of 60° dislocations with different stacking fault (SF) widths Δ between 30 and 90° partials. An increase of the dislocations density up to ND ∼ 107 cm–2 was found to result in a considerable growth of the intensity of the G‐lines with Em <0.513 eV. The factors, which promote the appearance of different Δ values for quasi‐equilibrium 60° dislocation structure, are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Photoluminescence of dislocations in plastically deformed GaN

Fresh (a/3) [ 1 1 2 ¯ 0 ] dislocations on the ( 1 1 ¯ 0 0 ) prismatic plane were introduced into GaN bulk crystals by plastic deformation at 950 °C. Photoluminescence (PL) studies at 11 K showed that the near band edge (3.48 eV) luminescence intensity decreased drastically in the deformed GaN, attributed to the introduction of a high-density of non-radiative recombination centers during plastic deformation. The yellow band (2.22 eV) luminescence decreased by plastic deformation, while several luminescence bands centered at 1.79, 1.92, 2.4 and 2.8 eV developed. The dependence of PL features on deformation and annealing indicates that yellow luminescence is not related to the native structure of dislocations in GaN.

Dislocation photoluminescence in silicon crystals of various impurity contents

The dislocation-induced photoluminescence (DPL) is studied at 4.2 K in plastically deformed silicon of various impurities content. The effect of oxygen on the DPL spectra is distinctly displayed in Czochralski (CZ) silicon at the density of introduced dislocations ND < 2 × 107 cm–2. The effect of phosphorous on the DPL is observed at concentrations above 1016 cm–3 in FZ and CZ silicon. The peculiarities of different DPL spectra are explained by supposing that D1 and D2 lines are associated with edge type jogs. The type of dislocations is discussed on which the defects responsible for each of these lines can be located. Some arguments are adduced concerning the effect of the length of ideal 60° dislocations on their radiation energy. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Statistical photoluminescence of dislocations and associated defects in heteroepitaxial GaN grown by metal organic chemical vapor deposition

Heteroepitaxial GaN films in general have very high concentration of defects and at the same time show broad photoluminescence (PL) peaks at energies below the band-gap energy $(3.4\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$, i.e., the so-called yellow (YL) and blue luminescence (BL) centered at 2.2 and $2.9\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, respectively. The origin of these PL peaks is commonly attributed to defects. The present paper studies the relationship of the yellow and blue luminescence with the defect structure by a combination of photoetching and photoluminescence. Nominally undoped ($n$-type) GaN layers were grown by metal organic chemical vapor deposition (MOCVD). By photoetching the perfect material between defects is removed and defect-related nanocolumns are formed. PL measurements of samples etched to various degrees allow the identification of the different PL features. A fully etched sample shows no PL signature related to any of the band edge features and BL is quenched completely, while the yellow luminescence is attenuated only to the degree to which the volume amount of GaN has been removed. Such behavior suggests that defects causing YL are not related to dislocations but are rather homogenously distributed throughout the layer in the form of point-like defects. The decrease of the BL intensity at $4.4\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ with excitation dose (bleaching) and the simultaneous increase in YL intensity for as-grown samples and the lack of such effects for etched samples imply a direct connection between the defect centers responsible for YL and BL.

Influence of microwave heating on dislocation photoluminescence in plastically deformed germanium

The effect of an X-band microwave electric field on the dislocation photoluminescence (DPL) in Ge is investigated. The influence of microwaves on the DPL depends strongly on the orientation of the microwave electric field Ew relatively to the glide plane, active during the plastic deformation. Comparing the data for Ew perpendicular and parallel to the glide plane, the influence of the microwave heating of 1D carriers in the dislocation bands and the 3D carriers, can be separated. It is found that the heating of 3D carriers leads to opposite effects on the DPL intensity in n- and p-type samples. On the contrary, the heating of 1D carriers results in an increase of the high-energy side of the DPL lines irrespective of doping. The obtained results give an additional argument in favor of the conclusion that the DPL corresponds to regular segments of dislocations rather than dislocation defects. A model to account for the obtained results is presented. [Russian Text Ignored].

Photoluminescence and splitting of dislocations in germanium

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