Abstract

The near-edge luminescence of zinc oxide epitaxial film grown via molecular-beam epitaxy on a sapphire substrate is studied. Upon an increase in optical excitation at room temperature, the luminescence spectrum changes radically and a new band appears with a maximum of ~3.17 eV. It has features of stimulated emission, i.e., a threshold of nonlinear growth and a narrowing of the half-width. A model of a one-dimensional amplifier and experimental data were used to calculate the gain spectrum, with maximal value being about 170 cm^–1. The theoretical approaches to calculate the Mott concentration were analyzed. It is shown for the first time that the observed stimulated emission near the threshold intensity originates from the second phonon replica of the exciton.

中文翻译：

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室温下ZnO结晶膜中激子-声子激发的发射

摘要

研究了通过分子束外延在蓝宝石衬底上生长的氧化锌外延膜的近边缘发光。在室温下增加光激发后，发光光谱会发生根本变化，并出现一个新的带，最大值为〜3.17 eV。它具有受激发射的特征，即非线性增长的阈值和半宽度的变窄。使用一维放大器模型和实验数据来计算增益谱，最大值约为170 cm ^–1。分析了计算莫特浓度的理论方法。首次表明，在阈值强度附近观察到的受激发射源于激子的第二声子复制体。