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Infrared reflection and transmission measurements of Be‐implanted GaAs have been made as functions of Be‐ion fluence and annealing temperatures from 500 to 800 °C. Semi‐insulating material was implanted with 280‐keV ions with fluences of 1×1015, 3×1015, 6×1015, and 10×1015 ions/cm2. Hole carrier concentrations calculated from the optical measurements as functions of fluence and annealing temperature compare favorably with those determined from sheet Hall‐effect data. The absorption cross section used was obtained from measurements of acceptor‐doped GaAs with concentrations similar to those of the implanted and annealed samples. After annealing at 500 °C a free‐hole plasma layer contribution to the electric susceptibility was observed by measurements of reflection interference effects. Except for the highest‐fluence case the disorder effect on the dielectric constant was largely removed by this anneal. For the highest‐fluence case the annealing results were more complicated. There are regions which still have significantly different optical properties due to residual disorder. The present results are consistent with redistribution effects produced by thermal aging at the higher temperatures.

The infrared reflectances of virgin and γ‐ray irradiated NaNO2 have been determined from the reflection spectra which have been investigated as functions of temperature (ranging from RT to 180 °C) and crystallographic orientation, and γ‐ray irradiation dose (4×107 and 3×108 rontgen.) over a frequency region between 700 and 2000 cm−1. Using the Kramers‐Kronig dispersion relation, we have obtained the dielectric function and oscillator parameters from the reflection spectra. These constants are used to explain the ferroelectric properties of NaNO2. In addition the observed differences between the reflection spectra of virgin and those of γ‐ray irradiated NaNO2 are explained using a broken‐bond model.

Free‐charge carriers in both room‐ and low‐temperature Be‐implanted GaAs were generated by annealing at 400, 450, and 475 °C and were observed by using both infrared reflection and electrical measurements. Annealing at 400 °C for 2 h removes homogeneously most of the damage‐related changes in the refractive index. Longer annealing (∼50 h) or shorter term annealing at higher temperature produces free carriers. A computer model including plasma effects was used to fit the reflection curves. In general the infrared analysis results and the electric data were in reasonable agreement. Results for the room‐temperature‐implanted samples show the free‐carrier density profile, approximated by joined half‐Gaussians, to be (i) a standard deviation for the deeper half‐Gaussian (σh≤0.1 μm), which is about the same or smaller than that observed by secondary ion mass spectrometry measurements (∼0.13 μm) for the Be profile, and (ii) a peak position 1.2 μm, which is deeper than the Be ion peak at 0.95 μm. Both peak positi...

Infrared reflection and transmission measurements were used to study the thermally induced regrowth of (100) oriented, Be‐implanted GaAs samples. The samples used in this study were implanted at low temperature (−100 °C) with 250‐keV Be ions to a fluence of 6×1015 cm−2. The samples were postannealed at temperatures ranging from 100 to 550 °C. Isochronal and isothermal annealing at a series of temperatures between 180 and 240 °C were performed. Infrared reflection spectra were analyzed by using a three or four layer dielectric model. Analysis of the annealing data suggests that an amorphous layer first anneals to a second metastable amorphous state and then becomes a damaged crystalline layer after annealing at 220 °C for 12 h. The observed regrowth is not by a simple epitaxial process. After annealing at 400 °C for 1 h, the damage in the layer is reduced sufficiently for the refractive index to recover almost to the preimplantation value. On annealing at 450 °C free carriers are observed. From the measure...

Infrared reflection and transmission measurements of GaAs implanted with large fluences of Be ions have been made as a function of post‐implantation annealing temperature. Annealing up to 400 °C resulted in decreases in the lattice disorder responsible for changes in the dielectric constant. This decrease appears to take place uniformly throughout the disordered layer rather than by an epitaxial process. Annealing at 400 °C for 2 h returns the dielectric constant to essentially the preimplantation value with no significant carrier activation being observed. Carrier activation is observed only after prolonged annealing at 400 °C, i.e., ≳50 h. Annealing for 1 h at 450 °C also produces measurable carrier activation. These results are in general accord with prior electrical data and transmission electron microscope measurements and suggest that the removal of the disorder‐induced changes in the dielectric constant and the activation of free carriers might involve different annealing processes.

Single crystals of SbSeI:Ni were grown by the Bridgman technique. The impurity optical absorption spectra of these single crystals were investigated at room temperature. We observed impurity optical absorption peaks at 4334, 7763, 8857, 8952, and 11 587 cm−1 due to nickel impurity. These impurity optical absorption peaks are assigned to the electronic transitions from the ground state 3T1(3F) to the excited states 3T2(3F), 3A2(3F), 1T2(1D), 1E(1D), and 3T1(3P) of Ni2+ ions sited at Td symmetry of the SbSeI host lattice.