Mid-infrared interband cascade light-emitting devices with improved radiance

We report interband cascade light-emitting devices (ICLEDs) emitting at λ ≈ 3.1mm, which produce generate higher radiance, output power, and efficiency than any other mid-infrared LEDs operating in continuous wave (cw) mode near and above room temperature. This is achieved in part by splitting the 22 LED stages into four groups placed at the antinodes of the near-normal optical field when the device is mounted epitaxial-side-down on a reflective metal contact. At an applied bias of 9.4 V and injection current of 0.6 A, an ICLED with mesa diameter 400 mm produces 2.9 mW of cw output power at T = 25°C, which corresponds to a radiance of 0.73 W/cm2/sr. The wall-plug efficiency ranges from 0.4% at low powers to 0.05% at the maximum output power.