| Mid-wave infrared (MWIR) laser diodes (λ = 3 to 5 μm) with high output power, high efficiency and high operating temperature have potential applications, such as: high resolution molecular spectroscopy, ultra low loss optical fiber communication, trace gas monitoring, air pollution analysis, open space communication, medical diagnostics, and target designation system in Military. However, MWIR semiconductor lasers suffer from low material quality, carrier loss due to leakage and Auger recombination, and high internal loss from free carrier absorption. Consequently, so far the output power from the laser diodes emitting at λ = 3 to 5μm has not reached the level required by most applications.; In order to improve the MWIR laser performance, InAsSbP based laser structures grown by Low pressure Metal-organic Chemical Vapor Deposition (LP-MOCVD) have been studied and developed.; InAsSb/InAsSbP DH was grown for the mid-infrared lasers emitting at 3 to 3.4 μm. Studies have been done to evaluate and optimize the growth conditions, such as: growth temperature, V/III ratio and growth rate et al., of the materials by using various characterization technologies. The laser structures have been designed and improved through the device modeling and the feed back of the laser performances. The recombination processes and carrier leakage have been investigated by studying the temperature dependence of the photoluminescence (PL) intensities. The outstanding of the material quality is evident in the distinct performance of the devices.; For the laser with the emitting wavelength longer than 3.4μm, InAsSb/InAs(SbP) strained MQWs have been successfully design and grown by LP-MOCVD. Modeling was done to optimize the structure parameters of the MQW laser, such as waveguide thickness, well thickness, the number of wells and critical thickness. Several characterization tools were used for the better understanding of the materials and the structures. X-ray diffraction and the dynamic simulation, and PL were used to evaluate the interface quality, band offset, well uniformity, critical thickness and the parameters of the MQW, such as the material composition and the thickness of the wells. The superior properties of the lasers indicate InAsSb/InAsSbP MQWs is a promising candidate for deep MWIR lasers. |
