Fabrication of high hole density p-type nitride semiconductor film crystal using alternating xrdoping techniques and its applications

在高效率照明、生化和医疗领域或高密度光存储领域，对高强度紫外(UV)激光二极管(LD)和发光二极管(LED)的需求越来越大。GaN和III-氮化物化合物半导体作为实现UV-LDS和LED的候选材料引起了人们极大的关注。然而，由于难以获得高Al含量的p型AlGaN，使用氮化物基材料很难实现高效的深紫外光LED或LDS。本工作的目的是利用交替共掺杂技术实现宽禁带p型AlGaN的高空穴密度，并开发工作在250-350 nm之间的高效深紫外光LED或LD。首先，我们证明了采用交流供气方法制备的Si/Mg共掺杂GaN外延膜具有高的空穴密度。在掺镁GaN中引入Si掺杂浓度可以显著提高空穴密度。然后，我们采用交流供气的方法制备了高Al含量的掺镁AlGaN。对于Al含量极高(46-53%)的掺镁AlGaN，我们采用交替供气的方法获得了空穴电导。我们还观察到了在AlGaN中引入Si/Mg共掺杂后激活能的降低。采用交流气体辅助生长的方法制备了310 nm波段的InAlGaN基高Al含量(53%)p型AlGaN深紫外发光二极管。在308-314 nm波长范围内，实现了RT脉冲下亚毫瓦级的输出功率。

The demands for high-intensity ultraviolet (UV) laser diodes (LDs) and light-emitting diodes (LEDs) are increasing for the application of high-efficiency lighting, biochemical and medical fields or high-density optical storages. GaN and III-nitride compound semiconductors are attracting considerable attention as candidate materials for the realization of UV-LDs and LEDs. However, it is difficult to achieve high-efficiency deep UV-LEDs or LDs using nitride-based materials because of the difficulty in obtaining High-Al-content p-type AlGaN. The purpose of this work is to achieve high-hole-density for wide-bandgap p-type AlGaN using an alternating co-doping technique, and to develop high-efficiency deep UV LEDs or LDs operating in the wavelength between 250-350 nm.First, we have demonstrated high-hole-density for Si/Mg co-doped GaN epitaxial filmes fabricating using alternating gas supply method. We obtained significant increase of hole density by introducing Si-doping concentration in Mg-doped GaN. Then, we fabricated high-Al-content Mg-doped AlGaN using alternating gas supply method. We obtained hole-conductivity for extremely high Al content (46-53%) Mg-doped AlGaN by using the alternating gas supply method. We have also observed the reduction of activation energy by introducing Si/Mg co-doping into AlGaN. We fabricated 310 nm-band InAlGaN-based deep UV light-emitting diodes (LEDs) with high-Al-content (53%) p-type AlGaN grown with the alternating gas supple method. We have achieved sub-milliwatt output power under RT pulsed operation in the wavelength between 308-314 nm.