Energy dispersive x-ray spectroscopy (EDS) was performed using a Zeiss Gemini 500 scanning electron microscope (SEM) operating at 20 keV which was equipped with an Oxford Instruments X-Max 80 detector. The spectrum was collected on the crystal surface that was in contact with the glass slide during growth. The atomic concentration was calculated using Oxford Instrument NanoAnalysis AZtec (Version 6.0) software.