Reversible tuning of two-dimensional electron gases in oxide heterostructures by chemical surface modification

Reversible control over the electricalproperties of the two-dimensionalelectron gas(2DEG) in oxideheterostructures is a key capability enabling practical applications. Herein, we report an efficient method to reversibly tune the chargecarrier density of the2DEG bysurface modification. We demonstrate both increasing and decreasing thecarrier density of the LaAlO3/SrTiO32DEG interfacevia application of functional phosphonicacids with molecular dipoles pointing either toward or away from the interface, respectively. In addition, in the case of the enhanced2DEG, we recovered the initial conductionproperties by exposing the samples to a basic solution. The tuning processes were highly reversible over repetitive cycles. These results reveal that thesurface modification is an efficient way to tune thecarrier density of2DEG in oxideheterostructures. This simple chemical approach offers a vast range of fabrication possibilities in versatile electronic device applications.

Source: Applied Physics Letters - November 9, 2016 Category: Physics Authors: H. Lee, N. Campbell, S. Ryu, W. Chang, J. Irwin, S. Lindemann, M. K. Mahanthappa, M. S. Rzchowski and C. B. Eom Source Type: research