High power 4.6 μm light emitting diodes for CO detection

We report on a powerful 4.6 mu m light emitting diode (LED), operating at room temperature, suitable for carbon monoxide gas detection. The source is based on a InAs0.55Sb0.15P0.30/InAs0.89Sb0.11/InAs0.55Sb0.15P0.30 symmetrical double heterostructure with large band offsets. To improve performance, the InAs0.89Sb0.11 ternary material in the active region was purified by using rare-earth ion gettering during liquid phase epitaxial growth. A pulsed optical output power in excess of 1 mW at room temperature has been measured, making these emitters suitable for use in cost-effective instruments for the environmental monitoring of carbon monoxide. The Auger coefficient of the InAs0.89Sb0.11 active region material was evaluated by analysis of the temperature quenching of the LED output power measured at constant current. II was found to be C-0 = 1.5 x 10(-26) cm(6) s(-1) with an activation energy of E-alpha = 31 meV, which is in good agreement with previous findings in the literature.