Photoluminescence of ion-implanted phosphors

Ion-implanted phosphors were prepared by implanting Sb in CaS at 25 keV with concentration ranging from 0.05 to 0.2% by weight. Samples of similar concentration were also prepared using the conventional technique. The spectral response under UV excitation of both types of samples is compared.     

Photoluminescence associated with impurity clusters in phosphorous doped silicon

Photoluminescence measurements as a function of excitation level and temperature are presented for Si(P) containing 7.5×10¹⁷ P atomd/cm³. The luminescence in Si(P) for intermediate concentrations in the range from 1×10¹⁶ to 2×10¹⁸ cm^?3 is interpreted in terms of recombination of trapped carriers at clusters of impurities.     

Photoluminescence from C ion-implanted and electrochemical etched Si layers

The microstructural and optical analysis of Si layers emitting blue luminescence at about 431 nm is reported. These structures have been synthesized by C⁺ ion implantation and high-temperature annealing in hydrogen atmosphere and electrochemical etching sequentially. With the increasing etching time, the intensity of the blue peak increases at first, decreases then and is substituted by a new red peak at 716 nm at last, which shows characteristics of the emission of porous silicon. CO compounds are induced during C⁺ implantation and nanometer silicon with embedded structure is formed during annealing, which contributes to the blue emission. The possible mechanism of photoluminescence is presented.     

Local phase transition near impurity center in neon cryocrystals

The effect of impurity centers (Ar, Kr or Xe) on the character of neon lattice rearrangement around these centers is studied by the VUV luminescence method. The temperature and time dependences of spectral intensity distribution are measured in a wide range of impurity concentrations. The observed stepwise changes in spectral characteristics are treated as a f.c.c.-h.c.p. phase transition in a local region. It is found that the region size may include 10³ atoms.     

Photoluminescence of sodium-implanted zinc selenide

Luminescence measurements indicate that Na acceptors implanted into ZnSe become optically active after annealing at 500°C. The spectra show a strong Na dependence for both the R series band and the I^Y₁ exciton line. In this work Ne-implanted and unimplanted samples were annealed and measured with the Na-implanted material to isolate defect-induced spectral features. Several new bands resulting from radiation damage are reported, along with annealing properties of the defect bands and Na-related luminescence.     

Photoluminescence investigation on impurity behavior in Sb-doped HgCdTe

Temperature-dependent (4.2–115 K) and excitation-intensity-dependent photoluminescence measurements have been performed on Sb doped HgCdTe samples with the emphasis on the impurity behavior of Sb doped in HgCdTe. In addition to the observation of the localized exciton, D°A°, band to band and bound to free transition related luminescence structures, the Sb-doping-related acceptor level of about 30 meV above the bottom of the valence band at 4.2 K has been obtained.     

Bound-to-bound and bound-to-free yellow emission of ion-implanted zinc telluride

Broad structureless emission bands centred near 580 nm have been observed in the low temperature cathodoluminescence emission spectra of zinc telluride single crystals implanted with zinc, argon or aluminum ions. Time-resolved spectroscopy measurements and measurements of the emission intensities as a function of sample temperature and of temperature of post-implantation isochronal annealing show that one yellow band occurs in both ZnTe : Zn and ZnTe : Ar and results from bound-to-free recombination involving an intrinsic donor level, probably due to a V_Te defect. In addition, there is a second yellow band present in ZnTe : A1 which is due to donor-acceptor pair recombination with the donors and acceptors identified with Al_Zn and V_ZnAl_Zn respectively.     

Self-activated luminescence of zinc sulfide

The nature of the luminescence of zinc sulfide in the spectral range (360), 380–420 nm (SAL) at 80K is analyzed. It is shown that the appearance of SAL radiation is accompanied by additional absorption in the region (350) 365–370 nm at 80K. The low-temperature spectra of sphalerite, exposed to different radiation and subjected to different treatment, are studied. The multiband luminescence of the isoelectronic sulfur impurity in ZnO deposits in the region 383–640 nm is discussed. It is concluded that SAL luminescence is attributable to the localization of excitons in ZnS on clusters, whose formation precedes the precipitation of the ZnO·S phase. The formation of oxygen clusters and deposits on dislocations in ZnS is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 60–66, February, 1987.     

Multiphoton impurity luminescence in zinc sulphide

Impurity luminescence is reported in ZnS(Cu) with two- and three-photon optical pumping. Experimental results are in good agreement with the nonlinear cross-section values obtained from other experiments and from theory.     

Spectral-luminescent characteristics of fluorophosphate glasses with zinc sulfide nanocrystals

Fluorophosphate glasses doped with ZnS are studied. The properties of ZnS nanocrystals formed are determined using X-ray-diffraction analysis and optical spectroscopy. The size and the band-gap width of these crystals are determined by the Tauc method. It is shown that ZnS nanocrystals luminesce in the visible spectral region with a low (2–3%) absolute quantum yield.     

Kinetics of electroluminescence of zinc sulfide

Time changes in the intensity of luminescence of zinc sulfide electroluminophores induced by rectangular unidirectional voltage pulses are considered. The origin of luminescence spikes that are observed under application and removal of voltage is discussed. Results of studies of these spikes and microscopic observations show that the light spikes observed under application of voltage can be ascribed to migration of holes that appear in barriers during the previous voltage pulse into the crystal interior. Moscow State University of Railway Transport, 15, Obraztsov St., Moscow, 101475, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 140–142, January–February, 1998.