Improvement in Spectroscopic Performance of Gallium Antimonide/Aluminum Arsenide Antimonide Heterostructure Energy-sensitive Detectors by Aluminum Oxide Surface Passivation

This thesis is devoted to improving the spectroscopic performance of the gallium antimonide (GaSb)/aluminum arsenide antimonide (AlAsSb) energy-sensitive detector. The heterostructure device is realized by integrating the GaSb absorber and the AlAsSb digital-alloy, combined with a field-control layer to optimize the electric field profile. This work attempts to enhance the energy resolving ability of the detector by lowering its surface leakage current, which is the dominant dark current source and limits the signal to noise ratio (SNR) of the detection system. To achieve the proposed goal, a layer of aluminum oxide (Al2O3) is deposited on the detector surface by ALD (Atomic Layer Deposition), which suppresses the formation of surface leakage path by interface chemistry between Al2O3 and the native oxides (e.g. Ga2O3 and Sb2O3). Well-improved dark current levels are measured in the Al2O3-passivated device, and the spectroscopic performance also indicates reduced electronic noise