Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Focussed Session: Frontiers in Laser Diode Physics II

HL 44.1: Invited Talk

Thursday, March 15, 2018, 15:00–15:30, EW 202

Development of AlGaN based UV Laser Diodes — •Ronny Kirste^1,2, Biplab Sarkar¹, Seiji Mita^1,2, Will Mecouch^1,2, James Tweedie^1,2, Qiang Guo¹, Andrew Klump¹, Ramon Collazo¹, and Zlatko Sitar¹ — ¹North Carolina State University, Raleigh, NC, USA — ²Adroit Materials, Cary, NC, USA

The AlGaN materials system offers unique opportunities to develop next generation UV lasers with emission ranging 210 to 350 nm. However, despite many efforts, no electrically injected laser diode with emission wavelength < 320 nm has been demonstrated yet. Among others, challenges for these devices include low doping efficiency, low carrier injection efficiency, absorbing layers and defects, and non-ohmic contacts. Here, we present recent advances in the growth and fabrication of UV laser diodes on single crystal AlN substrates. We will discuss all steps needed to achieve electrically injected UV lasing. First, it is shown that the MOCVD growth on AlN substrates results in high quality AlGaN layers with low defect concentration and excellent doping capabilities. Next, the design of the active region (MQW) is discussed and low threshold optically pumped lasing is demonstrated. Taking into account simulation results, the design and growth of a complete UV laser diode is shown and fabrication challenges are analyzed. Finally, we present electrical data and electroluminescence spectra from fabricated diodes and discuss the challenges that need to be addressed to realize the first electrically injected mid UV laser diode.