Thermal stability of the OH-Li complex in hydrothermally grown single crystalline ZnO

摘要

The thermal stability of the prominent 3577 cm~(-1) infrared absorption band in ZnO, assigned to an O-H stretch mode adjacent to a Li atom on Zn site (Li_(Zn)), is studied. Employing slow sample cooling after annealing, the 3577 cm~(1-) peak remains at temperatures ≤1250 ℃, consistent with previous reports. However, if the samples are cooled rapidly by quenching, the peak disappears after annealing for 1 h at 650 ℃. A dissociation energy of less than 2.5 eV is deduced for the OH-Li_(Zn) complex and the apparent high thermal stability after slow cooling is attributed to efficient recapturing of H by Li_(Zn). Moreover, deuterium (D) is found to replace hydrogen in OH-Li_(Zn) after 1 h at 700 ℃ in D_2 gas.