HgCdTe is the most widely used variable gap semiconductor material due to its fundamental properties and experimental flexibility. In spite of the successes achieved in the study of HgCdTe, many challenges still remain. A major one is to better understand and control the behavior of HgCdTe materials and heterostructures at elevated temperatures.; The results on the application of MBE technique to grow the high operating temperature (HOT) HgCdTe structures and the potential for near-room temperature operation of devices fabricated based on these structures are discussed in this thesis. Transport, recombination and generation processes are investigated in order to identify the parameters and mechanisms that limit the operation of these detectors at high temperatures, and also to propose possible solutions for increasing the operation temperature. Layer properties are analyzed from doping, scattering and recombination points of view. A dependence of the layer characteristics (minority carrier lifetime, mobility, trap energy and trap density) on the employed conditions is found. Dark current generating mechanisms are also investigated and a correlation with the material properties and with the theoretical models is established.; The heterostructure interfaces are studied to understand the mechanisms limiting the collection efficiency of the carriers and the current generation mechanisms. A combination of effects: non-equilibrium, heterostructure barrier formation, presence of Shockley-Read-Hall (SRH) centers are considered to explain the observed properties. To separate their influence, advances in controlled growth, processing and material quality are necessary. In spite of the encountered problems, HOT operation is demonstrated in terms of electrical characteristics, detectivity and spectral response.
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