Formation mechanisms of localized interstitial states in tetrahedrally bonded semiconductors

Evidence for a phosphorus-related interfacial defect complex at a GaP/GaNP heterojunction

“…An isolated P Ga antisite in its singly positive charge state was previously identified by electron paramagnetic resonance ͑EPR͒, characterized by an isotropic and strong HF interaction between the unpaired electron and a 31 P nucleus. [17][18][19][20] This interpretation of the early EPR results has been supported by several theoretical studies where an s-like deep-level state is expected for an isolated P Ga 1+ antisite, [20][21][22] which warrants the observed isotropic and strong HF interaction. In contrast, a p-like state was theoretically predicted for a P i interstitial.…”

“…In contrast, a p-like state was theoretically predicted for a P i interstitial. 20,21 Following the same line of arguments, many defects with a sizable HF interaction involving a central 31 P atom, commonly occurring in bulk GaP grown by liquid-encapsulated Czochralski, have been interpreted to involve P Ga ͑and not P i ͒ based on a strong s-like character of the wave function and its strong localization at the 31 P atom. [23][24][25][26][27][28][29][30] These assignments have received further support from theoretical prediction that defect formation energy during equilibrium growth greatly favors formation of antisites.…”

Ab Initio Studies of Hydrogen Defects in CdTe

“…We also have to mention that, due to partial occupation of the t 2 -level, H Cd can undergo Jahn-Teller distortion. This would result in the splitting of the t 2 -level into an occupied e-level and a half-filled a 1 -level, 41 along with a symmetry-lowering atomic relaxation. Our present electronic structure calculations, however, do not show either the splitting of the t 2 -level or the symmetry-lowering atomic distortion.…”

“…The second pair, derived mostly from the H orbitals, lies above the VBM. 41 The electron of the H atom is accommodated by the a 1 -state in the band gap. The position of this state depends on the potential of the defect center; for example, it has been found in the case of Cd and Te interstitial impurities at the tetrahedral site that the a 1 -state is located closer to the CBM and below the VBM, respectively.…”