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Abstract We report an anomalous effect on photoluminescence emission of disordered ZnO films related to the increase of optical emission as temperature increases. In order to verify the origin of… Click to show full abstract
Abstract We report an anomalous effect on photoluminescence emission of disordered ZnO films related to the increase of optical emission as temperature increases. In order to verify the origin of this effect, the ZnO film was annealed up to 500 °C and its PL emissions exhibited the expected Arrhenius behavior. We attribute this effect to the presence of traps that behave as potential fluctuations responsible for localizing the photogenerated carriers. These traps are originated from the disorder present in the as-grown sample and act in a temperature range associated to the depth of fluctuations. The influence of traps occurs up to a critical temperature T C associated to deepest trap level which is around tens of meV for ZnO.
Journal Title: Materials Letters
Year Published: 2017
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