Cathodoluminescence and Photoemission of Undoped and Mn Doped Lithium Tetraborate

<p>Lithium tetraborate (Li2 B4 O7) crystals are being developed for possible use in solid state neutron detectors. The 6Li(na) 3H and 10 B(na)7 Li reactions are the basis for neutron detection and a Li2 B4 O7 crystal enriched with Mn should show improved efficiency for neutron detection. There is a lack of fundamental characterization information regarding this useful material particularly with regard to its electronic configuration. Photoemission spectroscopy was used to determine the energy level structure of the Mn doped Li2 B4 O7 crystals. Measurements were made using ultraviolet photoemission spectroscopy (UPS) using synchrotron radiation on two different beamlines. The first was the 3 m toroidal grating monochromator (TGM) beam line confirming the presence of Mn. Secondly the normal incident monochromator (NIM) beamline studied the band gap states. Measurements were made at elevated sample temperatures to reduce charging effects. Photoemission studies provided evidence of Mn in the bulk crystal at 47.2 eV. Valence band analysis provided the presence of surface states but no acceptor sites. Cathodoluminescence studies were performed on undoped and Mn doped at beam energies from 5 to 10 KeV and at room temperature. Self trapped exciton emission states are evident in the undoped and Mn doped Li2B4O7 sample ranging in energies from 3.1 to 4.1 eV.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>