Emission Channeling Experiments Research Articles

Defect recovery of ion-implanted CdTe

The defect recovery of Bridgman and MBE grown CdTe implanted with In and Cd ions ( E = 60–350 keV) has been studied using the perturbed γγ angular correlation technique (PAC) sensitive to defects present in the immediate neighborhood of the implanted ions and photoluminescence spectroscopy (PL). Both the implanted species and the material influence the annealing behavior. Emission channeling experiments with implanted 111mCd ions show that already after implantation at 295 K the major fraction of implanted ions occupies substitutional lattice sites. The observed differences between Bridgman and MBE grown material indicate that the annealing behavior depends on the purity and crystal quality of the material. PL measurements on In-implanted CdTe show that for the overall recovery of the implanted layer annealing temperatures up to 800 K are necessary.

Emission channeling studies in semiconductors

Emission channeling allows the determination of the lattice location of radioactive impurities in crystalline solids at very low impurity concentrations of typically 10 17 cm −3 by measuring the channeling effects of electrons, positrons or α-particles emitted in the nuclear decay. Lattice sites of ion implanted dopants in semiconductors and subsequent recovery of implantation defects can be studied after implantation without amorphizing the lattice. An introduction to the emission channeling technique and experiments for the investigation of defect recovery and impurity lattice location after implantation of In, Cd and Te into III–V semiconductors in the temperature range 50 K to 600 K are presented. The α-emitting isotope 8Li offers a novel access to study the behavior of vacancy-like defects via lattice site changes of implanted Li probe atoms, α-emission channeling experiments in GaP and GaAs are compared to results from heavy ion implantation.