STRAINED TYPE II SUPERLATTICE INFRARED DETECTORS

THIS PROJECT WILL INVESTIGATE THE OPTICAL PROPERTIES OF A RECENTLY INVENTED CLASS OF TYPE-II, STRAINED-LAYER SUPERLATTICES MADE OF GAAS RELATED COMPOUNDS. THE NEW CONCEPT HAS ADVANTAGES, COMPARED WITH PREVIOUS EFFORTS, IN THAT SMALL BAND GAPS MAY BE ACHIEVED WITH SUFFICIENTLY THIN REPEATING LAYERS IN THE SUPERLATTICES. AS A RESULT, THEY HAVE GOOD OPTICAL-ABSORPTION PROPERTIES AND FAVORABLE ELECTRICAL-TRANSPORT PROPERTIES. ORIGINAL CALCULATIONS HAVEINDICATED THAT GA1-XINXSB/INAS IS THE BEST CHOICE FOR SUCH APPLICATION. VERY RECENTLY, IT HAS BEEN SHOWN TO HAVE THE HIGHEST ABSORPTION COEFFICENT AT 10MUM WAVELENGTH COMPARED WITH ALL OTHER SUPERLATTICE MATERIALS. PROJECT OBJECTIVES ARE TO FABRICATE, ACCORDING TO THEORETICAL MODELS, OPTIMIZEDDETECTOR STRUCTURES AND TO EVALUATE THEIR INFRARED OPTICAL PROPERTIES. THESE WILL BE FABRICATED BY MOLECULAR-BEAM EPITAXY (MBE), ACCORDING TO STRUCTURAL PARAMETERS DETERMINED FROM THEORETICAL MODELING. THE SAMPLE WILL BE CHARACTERIZED OPTICALLY AND EVALUATED FOR INFRARED DETECTIONAPPLICATIONS IN THE 2-17MUM REGION. THIS PROJECT WILL INVESTIGATE THE OPTICAL PROPERTIES OF A RECENTLY INVENTED CLASS OF TYPE-II, STRAINED-LAYER SUPERLATTICES MADE OF GAAS RELATED COMPOUNDS. THE NEW CONCEPT HAS ADVANTAGES, COMPARED WITH PREVIOUS EFFORTS, IN THAT SMALL BAND GAPS MAY BE ACHIEVED WITH SUFFICIENTLY THIN REPEATING LAYERS IN THE SUPERLATTICES. AS A RESULT, THEY HAVE GOOD OPTICAL-ABSORPTION PROPERTIES AND FAVORABLE ELECTRICAL-TRANSPORT PROPERTIES. ORIGINAL CALCULATIONS HAVEINDICATED THAT GA1-XINXSB/INAS IS THE BEST CHOICE FOR SUCH APPLICATION. VERY RECENTLY, IT HAS BEEN SHOWN TO HAVE THE HIGHEST ABSORPTION COEFFICENT AT 10MUM WAVELENGTH COMPARED WITH ALL OTHER SUPERLATTICE MATERIALS. PROJECT OBJECTIVES ARE TO FABRICATE, ACCORDING TO THEORETICAL MODELS, OPTIMIZEDDETECTOR STRUCTURES AND TO EVALUATE THEIR INFRARED OPTICAL PROPERTIES. THESE WILL BE FABRICATED BY MOLECULAR-BEAM EPITAXY (MBE), ACCORDING TO STRUCTURAL PARAMETERS DETERMINED FROM THEORETICAL MODELING. THE SAMPLE WILL BE CHARACTERIZED OPTICALLY AND EVALUATED FOR INFRARED DETECTIONAPPLICATIONS IN THE 2-17MUM REGION.