Detector arrays using Metal-Organic Vapour Phase Epitaxy (MOVPE) grown HgCdTe (MCT) on GaAs substrates have been in production at SELEX Galileo for over 10 years and are a mature technology for medium wave, long wave, and dual-band tactical applications. The mesa structure used in these arrays is optimised for MTF, quantum efficiency and dark currents. Further development of the technique has migrated to very long wave and short wave bands, mainly for space and astronomy applications, and for mid wave applications towards smaller pixels and higher operating temperatures. The emphasis of this paper is on recent experiments aimed at further improving HOT performance.