RADIATION-DISCRIMINATING IMPURITY-BAND-CONDUCTION LWIR PHOTODETECTORS

THE INNOVATIVE PROPOSED HERE IS THE DEVELOPMENT OF A NEW TYPE OF RADIATION-DISCRIMINATING, LONG-WAVELENGTH INFRARED (LWIR) DETECTOR BASED ON IMPURITY-BAND-CONDUCTION (IBC). THE NEW CONFIGURATION ENABLES ONE TO DISCRIMINATE BETWEEN GAMMA-RAY AND LWIR-INDUCED EVENTS. PAST USE OF IBC PHOTODETECTORS HAS SHOWN THAT INJECTED DARK CURRENT FROM THE CONTACTS IS A MAJOR PROBLEM LIMITING THEIR USE. FOR THE IBC CONFIGURATION OF INTERET HERE, THE USE OF A BIAS-DEPENDENT SUPERLATTICE (SL) TUNNELING STRUCTURE IS PROPOSED IS THE EXPLOITATION OF THE FACT THAT THERE IS A CRITICAL BIAS BELOW WHICH IBC IS ESSENTIALLY RANDOM AND ABOVE WHICH IBC IS PARALLEL TO THE ELECTRIC FIELD. THIS MAKES POSSIBLE THE STORAGE OF LWIR-GENERATED IONIZED DONORS AND ALSO THE READ-OUT OF GAMMA-RAY GENERATED ELECTRONS AND HOLES. THE IONIZED DONORS AREPERIODICALLY READ-OUT AND THIS FORMS THE BASIS OF LWIR DETECTION. PHASE I WOULD BE A FEASIBILITY STUDY, INCLUDING THE DETERMINATION OF THE OPTIMUM DEVICE DESIGN, OPERATING PARAMETERS, AND EXPECTED CURRENT VS. BIAS BEHAVIOR IN THE PRESENCE OF GAMMA-RAYS. THIS PHASE II GOAL IS THE SUCCESSFUL FABRICATION AND TESTING OF THIS DEVICE.