Piezo-spectroscopic induced perturbations for defects in cubic crystals under uniaxial stress applied along arbitrary low-symmetry crystal directions

A modification to supplement the experimental procedure required to identif y the symmetry of point and axial defects in silicon via photoluminescent p iezo-spectroscopy is reported. The modification requires that uniaxial stre ss be applied along a crystal direction of very low symmetry such that all orientational degeneracy is removed. Theoretical shift rate equations for a ll orientationally degenerate transitions and electronically degenerate sta tes in a tetrahedral host crystal are calculated for stress applied along a n arbitrary direction (X Y Z). These calculations are corroborated against the predictions of previous work and are used to successfully predict the s tress induced splitting of the 983.21 MeV Cd-A line in silicon under stress along the (1 3 6) crystal axis. The advantages this low-symmetry-axis pert urbation-spectroscopy (LSAPS) technique offers in conjunction with standard uniaxial stress analysis techniques are discussed.