P-n conductivity type conversion under ion milling in MOCVD p-CdxHg1-xTe/GaAs multi-layer hetero-structures is considered. It was revealed that CdTe (1 μm thick) passivation layer displayed the protective properties regarding ion milling action on active layer. P-n conversion at ion milling was observed in structures with 0.1-0.2 μm thick CdTe passivation layer; however, the converted depth (7 μm) was smaller than that in the similar homogeneous samples (15 μm). It was shown that the main properties of the converted p-n structures with thin CdTe layer were the same as in homogeneous samples. Ion milling resulted in forming of the typical n+- n - p+ structure with damaged n+-layer and main converted n-layer characterised by very low electron concentration. The relaxation of p-n structure electrical properties was also studied.
The optical filter for 8-12 microns spectral range on the base of MCT epilayer grown by Metal Organic Chemical Vapor Deposition (MOCVD) has been investigated. The CdTe mole fraction in CdxHg1-xTe equals x=0.24. The single-layer antireflection coatings for 10 μm peak wavelength have been deposed on the both sides of the filter. Transmission in 8-12 μm spectral range exceeds 70%. Transmission at 7 μm is of 40%, at 6 μm-10%, at 5 μm-less than 2%.
MWIR 128x128 Focal Plane Array (FPA) performance has been investigated. FPA has been fabricated on the base of HgCdTe active layers grown on (111)B GaAs substrate by Metal Organic Chemical Vapor Deposition (MOCVD). Histograms and diagrams of photodiodes current, responsivity and detectivity have been plotted for FPA with cutoff value 5,1μm at T=200K.