Novel InSb/InAsSb Quantum Dot Nanostructures for Mid-infrared Laser Applications

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We are trying to make semiconductor lasers for the mid-infrared (2-5 um) spectral range for a variety of practical applications including; chemical process control, environmental monitoring of atmospheric pollution and free space optical communications. At present it is impossible to obtain laser emission at room temperature due to low internal efficiency within the active region of the device. One way of minimising the unwanted processes that compete with the light generation is to arrange for this to take place inside a very small volume of material which is called a quantum dot . Recently at Lancaster we have successfully produced some quantum dot structures which emit light, but to be effective for use in a laser we need to make a sheet containing a large number of small quantum dots. The proposed fellowship seeks to build on our recent successful results and to obtain expert assistance from Dr. Solov'ev from the Ioffe Institute in Russia who is a world-leading authority in this area. Dr. Solov'ev's group has produced a dense array of self-assembled InSb quantum dots having a mean diameter of ~ 2.5 nm and a sheet density of ~ 10^12 cm-2 using a special technique to produce the InSb quantum dot nanostructures in the sub-monolayer thickness range. Dr. Solov'ev has developed a strong international lead by demonstrating room temperature light emission from his InSb quantum dot nanostructures and is enthusiastic to collaborate with us to develop a room temperature mid-infrared laser which contains these quantum dots in the active region.