Defect Photoluminescence of Undoping ZnO Films and Its Dependence on Annealing Conditions

Abstract

The undoping ZnO emitting films were deposited on Si substrates by dc reactive sputtering. There are two peaks of photoluminescence ͑PL͒, centered at 3.18 eV ͑ultraviolet͒, and at 2.38 eV ͑green͒, to be observed in the samples. We investigated the dependence of PL spectra on annealing temperature and annealing atmosphere. According to the calculation of defect levels and the relationship between PL spectra and annealing conditions, we supposed that the green emission of ZnO films corresponds to the local level composed of the antisite defect O Zn .

Near-band-edge slow luminescence in nominally undoped bulk ZnO

“…1,15 However, up to now, there is no consensus in the literature concerning the nature of the green emission band: several intrinsic defects such as V O , V Zn , Zn i , and O Zn have been proposed as well as extrinsic related defects such as Cu. [16][17][18][19][20][21][22][23][24][25][26][27][28] Despite the nature of the involved defect producing the 2.5-eV emission it is clear that if a spin-forbidden tripletsinglet transition is involved in the recombination mechanism ͑as expected for the oxygen vacancy͒ a slow luminescence should be observed, in good agreement with our results.…”

Photoluminescence and damage recovery studies in Fe-implanted ZnO single crystals

“…1,8,9 Donoracceptor pair ͑DAP͒ recombination at 3.22 eV followed by LO phonon replicas is usually present. 1,8,9 Besides these structured NBE emissions, deep-level structureless emissions are commonly observed in undoped ZnO single crystals, 10,11 powder samples, 12,13 thin films, 14,15 and nanocrystalline particles. 16 The centers responsible for the unstructured emission bands in the green, yellow, and red spectral regions are usually assumed to be due to different native defects in ZnO, such as oxygen vacancy (V O ), zinc vacancy (V Zn ), interstitial zinc, interstitial oxygen, and antisite defect (O Zn ).…”

“…16 The centers responsible for the unstructured emission bands in the green, yellow, and red spectral regions are usually assumed to be due to different native defects in ZnO, such as oxygen vacancy (V O ), zinc vacancy (V Zn ), interstitial zinc, interstitial oxygen, and antisite defect (O Zn ). [10][11][12][13][14][15][16] Until now, no consensus has existed in the literature concerning the nature of the defects where luminescence originates. In addition, theoretical studies propose controversial explanations to the green emission in ZnO due to transitions involving V Zn 17 and V O .…”

Photoluminescence properties of ZnO films grown by wet oxidation: Effect of processing

“…It is generally believed that the wide visible emissions are mainly due to the intrinsic defects such as zinc/oxygen interstitials, zinc/oxygen vacancies, antisite oxygen, and/or extrinsic impurities such as Cu [19][20][21][22][23]. Single ionised oxygen vacancy, zinc interstitial, and antisite oxygen might be responsible for the green emission in ZnO.…”