Publisher Summary A refractive index can be increased by ion implantation by changes in density and structure, by the addition of high-polarizability impurity ions, by a reduction of the plasma effect that increases the index and that is most important in the wavelength region far from the energy gap, and by absorption changing in the index in the region of the gap, that is, via the Kramers–Kronig relation. This chapter discusses the optical properties of implanted semiconductors, electrooptic components formed by ion implantation, general principles that determine most luminescent systems, effects of implantation temperature, luminescence centers in LiF-Mg-Ti radiation dosimeters, and use of line spectra in defect studies. In the LiF system, the luminescence bands are broad, and if alternative versions of the same complex exist, they cannot be resolved from the spectra. The addition, by implantation, of ions with incomplete inner electron shells opens up new possibilities as the lattice distortions of the free-ion energy levels are strongly perturbed by the defects in the neighborhood of the ion.

Optical Effects of Ion Implantation

A ‘year-2001’ set of nuclear quadrupole moments, Q, is presented. Compared to the previous, ‘year-1992’ set, a major revision of the value or a considerable improvement of the accuracy is reported for 6 3Li, 7N, 19 9F (197 keV, I = 5/2), 11Na, 13Al, 21Sc, 22Ti, 26Fe (14 keV, I = 3/2 Mossbauer state), 31Ga, 32Ge, 77 34Se (250 keV, I = 5/2 state), 35Br, 36Kr, 37Rb, 39Y, 40Zr, 100 45Rh, 50Sn (24 keV, I = Mossbauer state), 53I, 54Xe, 55Cs and 83Bi.

Spectroscopic nuclear quadrupole moments

[alpha]-quartz has been irradiated with heavy ions: [sup 19]F, [sup 32]S, and [sup 63]Cu at an energy of about 1 MeV/amu in order to cover a range of electronic stopping powers [ital dE]/[ital dx] between 2.4 and 9 keV/nm and [sup 58]Ni, [sup 86]Kr, [sup 128]Te, [sup 129]Xe, [sup 181]Ta, and [sup 208]Pb between 1 and 5.8 MeV/amu for [ital dE]/[ital dx][gt]7 keV/nm. The extent of the induced damage is determined using Rutherford backscattering ion channeling with a 2-MeV [sup 4]He beam. The damage cross section [ital A] is obtained using a Poisson law [ital F][sub [ital d]]=1[minus]exp([minus][ital A][phi][ital t]), where [phi] is the flux and [ital t] the irradiation time. This damage cross section is linked to the effective radius [ital R][sub [ital e]] through the relation [ital A]=[pi][ital R][sub [ital e]][sup 2], where [ital R][sub [ital e]] is the radius of an equivalent cylinder of damage. Using high-resolution electron microscopy, cylinders of amorphous matter have been observed, whose radius corresponds to [ital R][sub [ital e]] when the track is continuous (i.e., for [ital A][ge]1.3[times]10[sup [minus]13] cm[sup 2]; [ital R][sub [ital e]][ge]2 nm). A thermal-spike model is applied to calculate the radii of the observed tracks assuming that themore » observed amorphous cylinders correspond to a rapid quench of a molten liquid phase along the ion path. The model is applied only when the latent track is continuous and cylindrical. A good agreement is obtained taking into account that the initial spatial energy deposition on the electrons depends on the ion velocity.« less

Track formation in SiO2 quartz and the thermal-spike mechanism.

Ion implantation is a powerful technique for surface analysis and material modification and this review discusses the effects that specifically relate to optical properties of insulators. By selection of ion energy and ion dose one can inject trace impurities that control luminescence, generate optical absorption bands or complex defect aggregates, stimulate production of new crystalline phases or destroy crystallinity. Implantation invariably stimulates luminescence which provides a sensitive means of analysis to measure purity and near-surface defect concentrations. Post-implantation measurements reveal changes in many physical and chemical properties of the materials. Some, such as chemical reactivity, can increase a thousandfold, others such as birefringence, electro-optic and acoustic wave parameters are reduced. One major property which can be controlled is the refractive index; thus optical waveguides, and ultimately, complex integrated optical devices can be precisely defined by ion implantation.

https://iopscience.iop.org/article/10.1088/0034-4885/50/5/001/pdf

Optical effects of ion implantation

Ion implantation and annealing of crystalline oxides

Single crystals of α-Al 2 O 3 have been implanted at room temperature with 160 or 100 keV 57 Fe + ions and doses ranging from 10 16 Up to 10 17 ions cm −2 . The valence states and the local environment of implanted atoms as well as the damage in the implanted zone have been studied with the conversion electron Mossbauer spectroscopy technique associated with channeling and transmission electron microscopy. It was found that implantation introduces iron in sapphire in three charge states: Fe 2+ , Fe 3+ and metallic precipitates. Annealings in oxidizing or reducing atmosphere at temperature up to 1500°C convert all iron into Fe 3+ or Fe 0 respectively, and the precipitations of small oxide or metallic iron particles are observed correlatively with the rearrangement of the matrix.

Iron ion implantation effects in sapphire

Single crystals of Al 2 O 3 have been irradiated at GANIL with 3.5 MeV/amu Pb ions, at a temperature of ≌ 8 K. The fluence range extended from 4×10 11 to 1.2×10 12 ions cm −2 . The effects of high electronic excitation induced in the samples have been characterized by Rutherford backscattering on channeling (RBS) in conjunction with optical absorption measurements. Moreover, some samples preliminary implanted with 10 16 57 Fe + ions cm −2 at 110 keV and annealed at 1673 K during one hour were studied using conversion electron Mossbauer specroscopy (CEMS) in order to obtain complementary informations. Preliminary RBS results (77 K irradiations) indicate a damage cross section of ∼ 10 −13 cm 2 , consistent with a track radius of about 1.8 nm. The defect efficiency has been also investigated as a function of the electronic stropping power (d E /D x ) c .

High energy heavy ion irradiation effects in α-Al2O3

Spinel ferrite formation in iron implanted MgO crystals

The association of optical absorption, channeling and conversion electron Mossbauer techniques has been applied to the study of high dose iron implantation (6 × 1016 57Fe+.cm−2) phenomena in MgO single crystals. After implantation defects in the oxygen sublattice (F-type centers) and in the magnesium sublattice (V−-centers) have been observed as well as superparamagnetic iron precipitates (size ∽20 A) and Fe2+ ions. After thermal annealing for one hour at 700°C in argon atmosphere, all the iron species are converted mainly into Fe3+ ions contributing to the stabilization of F-type centers. A part of them is magnetically ordered even at room temperature, the other remaining paramagnetic down to 4.2 K. This could correspond to a bipartition in the Fe2O3 particle sizes: 50 to 80 A and <20 A respectively. Preliminary results in LiF implanted with 2 × 1016 57Fe+ ions. cm−2 are also reported

G. Marest

Papers

Iron ion implantation effects in sapphire

High energy heavy ion irradiation effects in α-Al2O3

Spinel ferrite formation in iron implanted MgO crystals

Optical, channeling and MÖssbauer studies of high dose iron implanted ionic crystals

Influence of temperature on nitrogen-implanted steels and iron