Abstract-AlGaAs/GaAs Terahertz Quantum Cascade Laser with Gold-Based Metal – Metal Waveguide

Anna Szerling, Kamil Kosiel, Piotr Prokaryn, Michał Szymański, Artur Trajnerowicz, Maciej Sakowicz, Piotr Karbownik, Mariusz Płuska, Michał Walczakowski, Norbert Pałka,

https://link.springer.com/chapter/10.1007/978-94-024-1093-8_17

In this chapter, we report the fabrication of Al0.15Ga0.85As/GaAs ~3 THz frequency quantum cascade laser (QCL). Its operation is based on 3-quantum-well (3QW) modules, where the GaAs QWs are separated by Al0.15Ga0.85As barriers. The laser’s active region is build by stacking the 228 modules. The lasers were fabricated as gold-gold waveguide devices and were gold-gold mounted on GaAs receptor wafers. The 300 nm Au/5 nm Ti claddings were made by sputtering, for which we used 8 × 10−3 mbar pressure level and 50 W generator power. The wafer-bonding process was performed in the temperature range 350–400 °C. The structures were wet etched into ridges with widths in the range 50–160 microns and lengths 1.8 mm. The lasers operated with threshold current densities ~650 A/cm2 at 77 K, when fed by 100–300 ns current pulses supplied with 300–1000 Hz repetition frequencies.