Growth and Characterization of a Semiconductor-Superconductor Heterostructure: the Hg 1−x Cd x Te/YBa 2 Cu 3 O 7−x System

A semiconductor-superconductor heterostructure has been successfully demonstrated in the Hg1−xCdxTe/YBa2Cu3O7−x (YBCO) system. YBCO films were deposited on LaAIO3 substrates by Pulsed Laser Deposition and Hg1−xCdxTe layers were subsequently grown between 160 °C and 200 °C. Heterostructures grown at 160 °C retain the key electronic properties of both the semiconductor and the superconductor. X-ray diffraction analysis indicates that the Hg1−xCdxTe films are oriented with the (111) planes parallel to the substrate. Mesa diodes were fabricated, and rectification in I–V characteristics was observed corresponding to carrier transport across the semiconductor/superconductor interface. For the heterostructure with a Hg0.75Cd0.25Te top layer, the thermal activation barrier to electron transport was found to be 82 meV from the temperature dependence of the zero-bias differential resistance.