Temperature-dependent mobility of a GaAs/AlGaAs heterostructure after deposition of MgO and superconducting YBa2Cu3O7−x

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Abstract
High quality YBa2Cu3O7−x films have been grown on MgO epitaxial buffer layers deposited onto a GaAs/AlGaAs heterostructure incorporating a two‐dimensional electron gas (2DEG). The critical temperature of the YBa2Cu3O7−x, Tc(0) was ≳80 K, and Jc≳2×104 A/cm2 at 77 K. Electron mobilities and concentrations of 2DEG substrates were measured at different stages in the formation of YBa2Cu3O7−x/MgO/2DEG structure. Room‐temperature mobilities and concentrations were unchanged after YBa2Cu3O7−x/MgO deposition, while low‐temperature mobilities were slightly degraded. It is found that the degradation of electron mobility is correlated to the high growth temperature of YBa2Cu3O7−x. Since the 2DEG is only 1200 Å from the substrate surface, this constitutes a sensitive demonstration of the viability of the semiconductor substrate under these growth conditions.