Optical emission related to basal-plane stacking faults in m-plane Zn1-xMgxO epilayers for 0 ≤ x ≤ 0.1

We investigate the optical properties of type-I-1 basal-plane stacking faults ( BSFs) in ZnO and Zn1-xMgxO by cathodoluminescence spectroscopy supported by envelope function calculations. We report on a quantum-well-like band alignment of the I-1 BSFs in ZnO taking into account the spontaneous polarization as well as an intrinsic self-screening effect on the polarization-related electric field. We present a systematic investigation of the luminescence properties associated with I-1 BSFs in Zn1-xMgxO for varying Mg content ( 0 <= x <= 0.1) using spatially and spectrally resolved cathodoluminescence spectroscopy. Both the near-band-edge emission and the luminescence line related to the I-1 BSF exhibit the expected blueshift and line broadening with increasing Mg content. We propose a band diagram to describe the recombination mechanism of excitons in a Zn1-xMgxO film containing I-1 BSFs. Based on a statistical analysis, we compile the experimentally obtained I-1 BSF emission energies of Zn1-xMgxO samples and establish a linear dependence of the I-1 BSF-related emission energy on the Mg content. This correlation provides an alternative way to identify the presence of I-1 BSFs in Zn1-xMgxO without the necessity of sophisticated transmission electron microscopy investigations.