We aim to break new ground in the science and technology of semiconductor light emitters. We focus on Gallium Nitride (GaN) based semiconductor microcavities (MCs) in which excitons and photons are strongly coupled to form exciton-polariton coupled modes, to fabricate coherent light emitters and parametric amplifiers (OPA), with major advantages over present technologies. The particular goals are: 1. Design, fabricate and test the first polariton laser - the demonstration of this new coherent light source would represent a major breakthrough with implications for both pure and applied science. We target both optically and electrically pumped devices at room temperature. 2. In very similar structures demonstrate ultrafast optical parametric amplifier (OPA) operation in compact micron size devices. The high exciton binding energies and large oscillator strengths of GaN provide the materials properties to achieve our goals. At the same time GaN MC technology is in its infancy and poses a number of challenges we are well placed to overcome. Although GaN devices are efficient light emitters, they have high thresholds for inversion due to the high carrier densities of states. MCs in the strong coupling regime overcome this intrinsic limitation, with up to 4 orders of magnitude lower density of states. Stimulation is thus much easier to attain, with the promise of low thresholds for coherent emission, an order of magnitude lower than present GaN lasers. Our goals require advanced crystal growth, device fabrication, spectroscopy, theory and device modelling, beyond the capabilities of any one laboratory. We have assembled a collaboration from leading laboratories around Europe, with the necessary expertise. Success will enable EU scientists, many of whom have pioneered the field, to achieve a real lead on an international scale. Our findings will also have wide applicability to other GaN-devices e.g. resonant cavity LEDs and VCSELs.
Fields of science
Funding SchemeSTREP - Specific Targeted Research Project
SO17 1BJ Southampton
G4 ONG Glasgow