Strong Visible and Near-Infrared Cathodoluminescence in Alkali Feldspar

In this study, cathodoluminescence (CL) spectroscopy at direct current and alternating current under the sample temperature condition of 40–293 K using different modulation frequencies is presented for alkali feldspar from the Dartmoor granite (UK). These feldspars contain strain-controlled lamellar crypto- and microperthites that are cross-cut by strain-free deuteric microperthites. The CL spectra of the alkali feldspar at room and low temperature confirm that the observed emission peaked at ～460 nm could be associated with Al-O^?-Al or Ti impurity centers, yellow emission ～560 nm could be associated with the presence of the centers such as radiation-induced defect centers, and ～756 nm emission could be associated with the Fe³⁺ impurity center on T₁ and T₂ sites. The consequence of their association is to produce different luminescence properties such as intensity, peak wavelength, and band shape.