Semiconductor lasers in the deep ultraviolet (UV) range have numerous potential applications ranging from water purification and medical diagnosis to high-density data storage and flexible displays. Nevertheless, very little success was achieved in the realization of electrically driven deep UV semiconductor lasers to date. In this paper, we report the fabrication and characterization of deep UV MgZnO semiconductor lasers. These lasers are operated with continuous current mode at room temperature and the shortest wavelength reaches 284 nm. The wide bandgap MgZnO thin films with various Mg mole fractions were grown on c-sapphire substrate using radio-frequency plasma assisted molecular beam epitaxy. Metal-semiconductor-metal (MSM) random laser devices were fabricated using lithography and metallization processes. Besides the demonstration of scalable emission wavelength, very low threshold current densities of 29~33 A/cm2 are achieved. Numerical modeling reveals that impact ionization process is responsible for the generation of hole carriers in the MgZnO MSM devices. The interaction of electrons and holes leads to radiative excitonic recombination and subsequent coherent random lasing.
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机译:深紫外(UV)范围内的半导体激光器具有众多潜在应用,从水净化和医疗诊断到高密度数据存储和柔性显示器。然而,迄今为止,在实现电驱动的深紫外半导体激光器方面几乎没有取得成功。在本文中,我们报告了深紫外MgZnO半导体激光器的制造和表征。这些激光器在室温下以连续电流模式工作,最短波长达到284nm。使用射频等离子体辅助分子束外延法在c蓝宝石衬底上生长具有各种Mg摩尔分数的宽带隙MgZnO薄膜。使用光刻和金属化工艺制造了金属-半导体-金属(MSM)随机激光器件。除了演示可扩展的发射波长外,还可以实现非常低的阈值电流密度29〜33 A / cm 2 sup>。数值建模表明,碰撞电离过程是导致MgZnO MSM器件中空穴载流子产生的原因。电子和空穴的相互作用导致辐射激子复合以及随后的相干随机激射。
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