HgCdTe nanostructures on GaAs and Si substrate for IR and THz radiation detecting

Abstract

Abstract. All-round studies of heteroepitaxial HgCdTe nanostructures (NS) growth on GaAs and Si substrates by molecular beam epitaxy have been carried out. In case of Si substrate HgCdTe NS's is very perspectives for IR detectors because of equal thermal expention coefficient with silicon read-out circuits. The problems of HgCdTe conjugations with Si at epitaxy connected with large differences in lattice mismatch and differences in chemical bonding that leads to antiphased domains. We found that the precise formation of transition layer (2 nm in thickness between Si substrates and first ZnTe buffer layer leads to growth HgCdTe NS's without antiphrasis domains. V-defects and etch pits densities are equal to 10 3 cm -2 and 10 7 cm -2 respectively. The HgCdTe/Si were used for fabrication photovoltaic 640×512 MWIR focal plane arrays. The operability for 1/2 = 4.2 m (77К) was over 97%. The response (Sv) and NETD were as 1,5×10 9 V/W and less 20 mK respectively. We developed the precise growth of symmetric and antisymmetric HgTe QW. We found the following effects: the presence 2D electron gas with high mobilities over 5×10 5 cm/V×s in doped HgTe QW, the presence @D holes and electrons in undoped HgTe QW and high sensitivity to linear and circular polarized IR and THz radiation in 6 -400 m region.