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

高强度紫外（UV）激光二极管（LD）和发光二极管（LED）在高效照明、生物化学和医疗领域或高密度光存储的应用中的需求正在增加。GaN和III族氮化物化合物半导体作为用于实现UV-LD和LED的候选材料吸引了相当大的关注。然而，由于难以获得高Al含量的p型AlGaN，因此难以使用氮化物基材料实现高效率的深UV-LED或LD。本工作的目的是利用交替共掺杂技术实现宽带隙p型AlGaN的高空穴密度，并开发工作在250-350 nm波长范围内的高效率深紫外LED或LD。首先，我们证明了利用交替供气方法制备Si/Mg共掺杂GaN外延膜的高空穴密度。通过在Mg掺杂GaN中引入Si掺杂浓度，我们获得了空穴密度的显著增加。然后，我们采用交替供气的方法制备了高Al含量的Mg掺杂AlGaN。采用交替供气的方法，在极高Al含量（46-53%）的Mg掺杂AlGaN中获得了空穴电导率。我们还观察到通过在AlGaN中引入Si/Mg共掺杂降低了激活能。采用交替供气法生长高Al含量（53%）p型AlGaN，制备了310 nm波段InAlGaN基深紫外发光二极管（LED）。在308-314 nm波长范围内，我们已经实现了亚毫瓦级的RT脉冲输出功率。

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.