We present the concept and the results of pilot measurements of tunneling in
a system {Al/δSi​-GaAs} under pressure up to 2 GPa at 4.2 K. The
obtained results may indicate the following: the barrier height for
{Al/δ-GaAs} equals to 0.86 eV at P=0 and its pressure coefficient is 3meV/kbar; charged impurity density in the delta-layer starts to drop from
4.5×1012cm−2 down to 3.8×1012cm−2 at about 1.5
GPa; metal-insulator transition may occur in 2DEG at about 2 GPa