Showing papers on "Photoluminescence published in 1971"
4,512 citations
TL;DR: In this paper, photoluminescence arising from distant donor-acceptor pair recombination in GaN has been identified and analyzed, and the recombination rate constant, W ( O ) = (3 ± 2) x 10 7 sec − is consistent with a direct, fundamental energy gap.
221 citations
108 citations
TL;DR: In this article, the conduction-band structure of In1−xGaxP has been studied by cathodoluminescence (CL) and photoluminecence (PL).
Abstract: The conduction‐band structure of In1−xGaxP has been studied by cathodoluminescence (CL) and photoluminescence (PL). An accurate determination of the direct energy gap (± 10 meV) as a function of alloy composition (Δx = ± 0.025) is achieved by the simultaneous electron probe microanalysis of alloy composition and spectral measurements of the CL excited by the microprobe electron beam. Similar measurements in InP, GaAs, and GaAs1−xPx, as well as absorption edge measurements and the temperature dependence of the PL spectrum, indicate that essentially free‐carrier recombination is observed in the PL and CL measurements of lightly n‐type In1−xGaxP at 300 °K. These results indicate that the ``cross over'' between the direct and indirect conduction‐band minima occurs at the composition x = 0.74 and energy gap = 2.26 eV.
104 citations
TL;DR: Germanium was used to dope both the n and p layers of GaAs grown when molecular beams containing Ge, Ga, and As2 simultaneously impinged on the substrate surface.
Abstract: Germanium was used to dope both the n and p layers of GaAs grown when molecular beams containing Ge, Ga, and As2 simultaneously impinged on the substrate surface. The formation of n‐ or p‐type layers is dependent on the ratio of As2/Ga in the molecular beam and the substrate temperature. We describe the process used for the doping as well as the photoluminescence spectra from these layers.
96 citations
TL;DR: In this article, the authors show that the nature of relaxed exciton states changes discontinuously from free to self-trapped excition as the composition x exceeds ∼ 0.45, and the transition can be explained by attainment of sufficiently strong exciton-phonon coupling wehn the alloy composition is varried.
67 citations
TL;DR: In this article, the photoluminescence from three defect centers in diamond has been investigated and it was shown that the lines at 2.887 eV, 2.954 eV and a broad absorption extending from 2.8 eV to higher energies are associated with the 1.673 eV defect.
Abstract: Measurements are reported of photoluminescence from three defect centres in diamond which have characteristic absorption and emission lines at 1.673 eV, 1.944 eV and 2.498 eV respectively. When excited with plane polarized light the emission from the 1.673 eV centre was found to be unpolarized in agreement with a centre possessing tetrahedral symmetry. Analysis of the polarization of emission of the other centres suggests that the symmetry of the 1.944 eV centre is either monoclinic I or trigonal, and that of the 2.498 eV centre is monoclinic I. A comparison of the absorption and excitation spectra indicates that the lines at 2.887 eV and 2.954 eV and a broad absorption extending from 2.8 eV to higher energies are all associated with the 1.673 eV defect.
63 citations
TL;DR: In this article, it has been proved that the expression for yield, describing the process of quenching by foreign absorbing substances, turns into the expression which was previously obtained by Forster, which also takes into account the self-quenching of photoluminescence in the range of large concentrations.
Abstract: In the theory presented the following phenomena have been analysed from a uniform point of view: 1) concentration quenching 2) quenching by foreign absorbing substances 3) concentration depolarization of photoluminescence. The participation of primarily unexcited molecules of the donor in the process of energy transfer to the molecules of the acceptor as well as the remigration of excitation energy have been considered in the theory. It has been accepted that in case 1) the role of the molecules of the acceptor is carried out by dimers. Expressions for the quantum yield as well as emission anisotropy of photoluminescence have been obtained. It has been proved that the expression for yield, describing the process of quenching by foreign absorbing substances in the particular case whenγ
D
≪γ
A
turns into the expression which was previously obtained byForster. The expression for emission anisotropy which also takes into account the self-quenching of photoluminescence describes the effect of repolarization appearing in the range of large concentrations. A discussion of the results obtained is presented
60 citations
TL;DR: In this article, surface structures were observed during molecular beam epitaxial growth of GaAs in situ in an ultrahigh vacuum high energy electron diffraction (HEED) system.
Abstract: Surface structures were observed during molecular beam epitaxial growth of GaAs in situ in an ultrahigh vacuum high energy electron diffraction (HEED) system. The surface structures were related to the relative populations of gallium and arsenic on the substrate surface when the intensities of gallium and arsenic in the molecular beam were varied during growth. On the GaAs ( 111 ) face a ( 111 )-2 surface structure is interpreted in terms of an arsenic-rich surface condition and a ( 111 )-√ 19 structure is interpreted in terms of a gallium-rich condition. Only the (111)-2 surface structure was observed on the (111) face. The presence of these different surface structures under different growth conditions is interpreted in terms of rearrangements of the unshared bonds of the atoms on the crystal surface. Photoluminescence measurements were used to investigate the radiative recombination characteristics of the films grown with either a ( 111 )-2 or a ( 111 )-√ 19 structure present on the surface. The results show that the near gap photoluminescence intensity from a film grown under the latter condition is much higher than that from the former. A broad photoluminescence peak ∼ 0.1 eV below the band gap energy is observed on all epitaxial layers grown with the ( 111 )-2 structure present on the surface. The peak may be reduced by annealing and may be attributed to centers associated with Ga vacancies.
60 citations
39 citations
TL;DR: In this paper, the phase diagram calculations based on Darken's quadratic formalism to describe the ternary liquid in equilibrium with the pseudobinary solid are in good agreement with the bandgaps of the grown layers determined by photoluminescence.
Abstract: Zinc‐doped InAsP liquid epitaxial layers with bandgaps between 0.4 and 1.34 eV were grown on InAs and InP substrates. The grown layers were 2–4‐μ thick with mirror‐smooth as‐grown surfaces. Preliminary phase diagram calculations based on Darken's quadratic formalism to describe the ternary liquid in equilibrium with the pseudobinary solid are in good agreement with the bandgaps of the grown layers determined by photoluminescence. The InAsxP1−x–Cs2O heterojunction barrier height as a function of composition has been measured using photoemission. For InAs the barrier is at 1.24 eV, and it decreases with decreasing arsenic concentration to a value of 1.16 eV for InAsP with a 1.27‐eV bandgap. For InAsxP1−x samples with bandgaps in the range 1.17–1.34 eV, high escape probabilities and efficient photoemission were observed. A typical cleaned (not cleaved) sample with a bandgap of 1.19 eV has a sensitivity of 600 μA/lm, 70 μA with a lumen source through a 2540 ir filter, a quantum efficiency of 1.5% at 1.06 μ, a...
TL;DR: In this paper, low-temperature photoluminescence efficiency measurements confirm that recombination in the bulk semiconductor is unaffected by the presence of these low concentrations of As, In, and Al.
Abstract: The addition of low concentrations (≲1%) of As, In, or Al to the p side of GaP junctions, where exciton recombination at N or Zn, O centers generates green and red electroluminescence (EL), respectively, drastically decreases the quantum efficiency η of the junctions. The decrease in η is due to increased nonradiative recombination at deep centers in the junction space charge, while recombination outside the space charge is unchanged according to measurements of the EL decay time. Low‐temperature photoluminescence efficiency measurements confirm that recombination in the bulk semiconductor is unaffected by the presence of these low concentrations of As, In, and Al. The junctions were formed using liquid epitaxial techniques. Using InxGa1−xP layers, where the alloy composition was accurately determined using radioactive tracer techniques, the composition dependence of the transition energies of the N and S bound excitons was measured by low‐temperature absorption and luminescence studies.
TL;DR: In this article, photoluminescence studies are made for GaxAl1-xAs mixed crystals doped with Te, Sn, Si, Ge and Zn.
Abstract: Photoluminescence studies are made for GaxAl1-xAs mixed crystals doped with Te, Sn, Si, Ge and Zn. Broad low energy emission bands as well as near bandgap emission bands are observed. The near gap bands show changes in characteristics due to the transition from direct to indirect bandgap at composition (1-x)\cong0.36. The low energy bands can be classified into two types. Bands of the first type are observed in the direct gap region and arise from the same origin as in GaAs. Bands of the second type are observed both in the indirect and direct gap regions except for small (1-x). From the composition dependence, it is suggested that the bands of the latter type are associated with the deep donor levels induced from the [100] conduction band minima.
TL;DR: In this article, the degree of polarization of the photoluminescence was used to determine the spin-polarized electrons in the conduction band of p-type GaSb by excitation with σ+ or σ− polarized light.
Abstract: Spin-polarized electrons are created in the conduction band of p-type GaSb by excitation with σ+ or σ− circularly polarized light. The degree of polarization of the photoluminescence is used to mea...
TL;DR: In this article, the effect of the surface field generated near the Au-CdS interface of an Au-Schottky-barrier diode has been studied under a variety of CdS single crystals.
Abstract: Photoluminescence (edge emission) in a variety of CdS single crystals has been studied under the influence of the surface field generated near the Au–CdS interface of an Au–CdS Schottky‐barrier diode. Experimentally, above bandgap radiation is incident upon a semitransparent Au film evaporated on an air‐cleaved CdS surface. Free electrons and holes are generated within the region of the high barrier field which extends on the order of 0.5 μ into the crystal bulk. Variations of diode bias as small as 2.5 V were found to be sufficient to alter the luminescence efficiency by nearly two orders of magnitude. A model is presented (emphasizing the rapid removal of photoinjected free carriers from the barrier) which qualitatively accounts for the major features of the observed effects.
TL;DR: In this article, photoluminescence from the oxygen isoelectronic trap implanted into ZnTe is investigated for various ion doses and annealing conditions, and the expected isotope shift is observed in the spectrum for samples implanted with 18O without the usual 16O contamination found in conventionally doped samples.
Abstract: Photoluminescence from the oxygen isoelectronic trap implanted into ZnTe is investigated for various ion doses and annealing conditions. The characteristic oxygen spectrum is observed after annealing either in zinc vapor or in vacuum. The anticipated isotope shift is observed in the spectrum for samples implanted with 18O without the usual 16O contamination found in conventionally doped samples. In isochronal anneal studies the intensity of the oxygen luminescence peaks at 300°–400°C. For samples annealed in Zn vapor the anneal curves show a slight dip at higher temperatures, whereas for vacuum anneals the curves fall off rapidly. The dose for maximum luminescence is found to be a function of the anneal temperature. Much of the gross lattice damage is annealed at 500°C; at this temperature the luminescence peaks at a dose of ∼1014 ions/cm2, corresponding to an implanted concentration of ∼2×1018/cm3. Although reasonable luminescence intensities have been achieved, compared with conventionally doped samples, only ∼5% of the light intensity anticipated on the basis of the implant dose is actually observed as emission from the oxygen isoelectronic trap.
TL;DR: In this paper, photoluminescence measurements have been made on thin, epitaxial layers of n-GaAs to which an electric field is applied, and a fairly good agreement with theory is obtained, although variations between samples are too great to give clear support to the detailed model of Rees as opposed to the more phenomenologically drifted Maxwellian.
Abstract: Photoluminescence measurements have been made on thin, epitaxial layers of n‐GaAs to which an electric field is applied. Field‐dependent spectra are obtained corresponding to band‐to‐band recombination at 77 and 200°K, and from these the changes in electron distribution function are derived, allowance being made for the distributions of light and heavy holes. A fairly good agreement with theory is obtained, although variations between samples are too great to give clear support to the detailed model of Rees as opposed to the more phenomenologically drifted Maxwellian. The field suppression of the exciton peak is marked and is not adequately explained by present theory.
01 Jan 1971
TL;DR: In this paper, the authors studied the channeling and photoluminescence properties of GaP implanted with Bi at an elevated temperature (450°C), and compared with samples implanted at room temperature (25°C) and subsequently annealed at 450 °C.
Abstract: Channeling and photoluminescence are studied in GaP implanted with Bi at an elevated temperature (450°C), and comparison is made with samples implanted at room temperature (25°C) and subsequently annealed at 450 °C. It is found that the channeling behavior is significantly improved by the hot implant, and that the Bi is ~75% substitutional. However, no photoluminescence is observable unless the samples are annealed at temperatures in excess of 600 °C. After annealing at 800 °C, the luminescence intensity obtained from the hot-implant samples is compared with those implanted at room temperature, for doses of 2 · 1013 and 1.8-1015 Bi ions/cm2. For the low-dose case, hot implants increase the luminescence by only ~8%, whereas the weak luminescence observed from the high-dose samples increases by ~65%. The spectral features of the luminescence provide evidence for the presence of both strain and competing damage centers. A detailed study of the channeling angular distribution indicates that the low optical efficiencies cannot be explained by assuming that a substantial fraction of the implanted Bi ions occupy substitutional Ga sites, where they would be optically inactive.
TL;DR: In this paper, a comparison of the photoluminescent and electroluminescence spectra of Er3+ doped ZnSe was performed and the emission sites in each case were different in origin.
Abstract: The authors present a comparison of the photoluminescent and electroluminescent spectra of Er3+ doped ZnSe and establishes that the emission sites in each case are different in origin. Two types of rare earth sites have been observed in electroluminescence and six sites in photoluminescence. The defect structure of each site is discussed.
TL;DR: In this paper, photoluminescence and optical absorption have been observed from GaP implanted with nitrogen to a concentration of 1019cm3, after annealing at 800-900°C.
TL;DR: In this article, the effects of elevated temperature annealing procedures on the photoluminescent properties of ZnTe crystals were investigated and a correlation existed between the photophotonicity properties of the crystals and electroluminescence properties of M.I.S. devices fabricated from annealed crystals.
TL;DR: A photoluminescence band at 1.40 eV has been observed at 90 °K only at the interface between the epitaxial layer and the substrate in the vapor-grown GaAs crystal.
Abstract: A photoluminescence band at 1.40 eV has been observed at 90 °K only at the interface between the epitaxial layer and the substrate in the vapor‐grown GaAs crystal. The defect responsible for the band is considered to correlate with a shift of the Fermi level toward the valence band in this interface region and to be related to the acceptor created in GaAs bulk crystal which is heat treated in H2. The defect may be the deeper of two kinds of acceptors associated with the Si impurity on an As site in GaAs crystal.
TL;DR: In this article, an analysis is given of the dependences of steady state photoluminescence intensity and the kinetics of the photolumininescence decay on temperature and exciting light intensity and this leads to a scheme of electron transitions via radiative centres with the following parameter values: energy position (EV+0.93 to 1.5 eV), concentration (N = 1015 to 1016 cm−3), electron and hole capture coefficients (γn = 5×10−13 cm3 s−1, γp = 2×× 10−
Abstract: Investigations of the low energy emission bands at 0.93 to 1.0 eV in Te-doped n-type GaAs were made. An analysis is given of the dependences of steady state photoluminescence intensity and the kinetics of the photoluminescence decay on temperature and exciting light intensity and this leads to a scheme of electron transitions via radiative centres with the following parameter values: energy position (EV+0.5 eV), concentration (N = 1015 to 1016 cm−3), electron and hole capture coefficients (γn = 5×10−13 cm3 s−1, γp = 2××10−6 cm3 s−1 at T = 77 to 400 °K).
[Russian Text Ignored]
TL;DR: The low temperature optical spectra associated with the thallium ion in doped samples of ammonium chloride have been investigated in this article, where the authors present absorption, photoluminescence and luminescence excitation spectra for this CsCl-structure (cubic) phosphor.
TL;DR: In this article, a luminescence peak at 9140 A is introduced into the spectra of all implanted and annealed GaAs, attributed to an acceptor level created by As vacancies.
Abstract: Photoluminescence measurements at 77°K and Rutherford scattering of 450 keV protons were used to study radiation damage and annealing in ion implanted GaAs. The characteristic band edge luminescence (8225 A) in GaAs is completely quenched by ion implantation. Photoluminescence measurements on samples which were isochronally annealed show a single annealing stage at 600°C. A luminescence peak at 9140 A is introduced into the spectra of all implanted and annealed samples. This peak is attributed to an acceptor level created by As vacancies. The intensity of the peak is greatly reduced by protecting the surface of implanted layers with SiO2 during annealing. Rutherford scattering measurements on isochronally annealed samples reveal two annealing stages. A 300°C annealing stage is observed on samples which have an initial aligned yield less than random while a 650°C stage is observed on samples which have an initial aligned yield equal to random.