16:45 〜 17:00
▲ [12p-N101-14] Reporting 100 kA cm-2 Injection Current Density in 283nm-Band AlGaN UVB LED
キーワード：AlGaN, deep-ultraviolet (DUV) laser diodes (LDs), Optical and electrical pumping
Recently, our group also demonstrated to AlGaN DUV LD grown low cost AlN template on C-Sapphire substrate with improved injection current density of 48 kA-cm-2, however some abnormal stimulated oscillations were also observed for the first time in the DUV LD at 273 nm emission. However, electrically-pumped AlGaN-based 283-band UVB LD was quite challenging due to both the issue of low injection current density from p-side toward the multi-quantum-wells (MQWs) and poor optical confinement. Therefore, in this work both the conventional flat-type ud-AlGaN cladding layer and p-AlGaN hole source layer (HSL) were replaced with Al-graded undoped (ud)-AlGaN CL as well as Al-graded Mg-doped p-AlGaN HSL in AlGaN-based 283-band UVB LDs grown on AlN template.
Based on the improved AlGaN-based MQWs, we re-designd our LD structure and grow electrically pumped UVB LD for better carrier injection. Based on Hall`s effect measurement, quite low resistivity of ~ 24 Ω-cm and hole mobility of ~ 9.6 cm2 V-S-1 along with realtively high hole concentration of ~ 2.6×1016 cm-3 in the Al-graded p-AlGaN HSL were confirmed. The mesa structure was formed by the inductively coupled plasma (ICP) dry etching method to expose the surface of the n-AlGaN base layer for electrical pumping contact. Finally, LDs structure with ridged structure of area ~ 4 µm × 400 µm were processed including fabrication of gold pad and mirror structure. The electrically pumped LD was demonstrated under pulse operation at RT and voltage-current density characteristic reached to 1700 mA at 283nm emission. Ultimately, UVB LD with improved injection current density of 100 kA-cm-2 was realized and stimulated oscillations were not observe this time. We acknowledge to the financial support provided by NEDO, Japan.
Based on the improved AlGaN-based MQWs, we re-designd our LD structure and grow electrically pumped UVB LD for better carrier injection. Based on Hall`s effect measurement, quite low resistivity of ~ 24 Ω-cm and hole mobility of ~ 9.6 cm2 V-S-1 along with realtively high hole concentration of ~ 2.6×1016 cm-3 in the Al-graded p-AlGaN HSL were confirmed. The mesa structure was formed by the inductively coupled plasma (ICP) dry etching method to expose the surface of the n-AlGaN base layer for electrical pumping contact. Finally, LDs structure with ridged structure of area ~ 4 µm × 400 µm were processed including fabrication of gold pad and mirror structure. The electrically pumped LD was demonstrated under pulse operation at RT and voltage-current density characteristic reached to 1700 mA at 283nm emission. Ultimately, UVB LD with improved injection current density of 100 kA-cm-2 was realized and stimulated oscillations were not observe this time. We acknowledge to the financial support provided by NEDO, Japan.