Observation of Shubnikov de Haas oscillations due to interfacial two dimensional electron gas in epitaxial HgCdTe on CdZnTe heterostructure

The presence of two dimensional electron gas associated with misfit dislocation network at the compositionally graded interface of HgCdTe/CdZnTe heterostructure prepared by liquid phase epitaxy has been reported. Shubnikov-de-Haas (SdH) oscillations were observed in Ga-diffused n-type HgCdTe/CdZnTe heterostructures in the temperature range of 1.8–10 K with magnetic field swept up to 8 T. The epilayer was thinned down from an initial thickness of ∼23 μ m to the graded interfacial region of ∼3 μ m in steps of ∼10 μ m each and the magneto-transport measurements were done at each differential etch step. The SdH oscillations observed at three steps were coherent with all the peaks occurring at same magnetic field value. An estimation of electron effective mass and sheet carrier density helped conclude that these SdH oscillations are due to a 2DEG present at HgCdTe–CdZnTe hetero interface. It is proposed that the stress field of misfit dislocation network in the interfacial region is responsible for the formation of this 2DEG. (paper)