Paramagnetic point defects in boron-implanted Hg_(0.7)Cd_(0.3)Te and CdTe

Abstract

This paper describes the initial observations of electron paramagnetic resonance (EPR) spectra from Hg_(0.7)Cd_(0.3)Te and CdTe after implantation with boron ions. Sharp and nearly isotropic EPR signals with the free‐electron g values were easily detected at low temperatures (i.e., ≤ 78 K) when the boron ion implant dose was 1×10^(16) ions/cm^2 or larger. For identical implant conditions, more intense signals and narrower peaks were obtained from Hg_(0.7)Cd_(0.3)Te samples when compared to the spectra for CdTe. However, the g factors for all implanted Hg_(1−x)Cd_xTe samples appear to be equivalent and are very similar to the values reported for the dangling‐bond defects in other ion‐implanted semiconductors. The EPR spectra produced by the boron implants do not seem to correspond to either the degenerate conduction electron bands that form in ion‐implanted Hg_(1−x)Cd_xTe or the shallow donor states previously found in chemically doped CdTe. When implanted crystals are cooled below 4 K, partially resolved two‐component line shapes are observed at some orientations. Increasing temperature causes these two‐component lines to collapse into nearly Lorentzian line shapes with temperature‐dependent widths. This behavior is consistent with a thermally activated process by which the paramagnetic spins hop between inequivalent locations.