The theory of tunnel current-voltage (I-V) characteristics of metal-semicon
ductor junctions based on the self-consistent solution of the Poisson equat
ion allows to gel the Schottky-barrier height and the charged impurity conc
entration directly from the tunneling data. This approach was applied to th
e analysis of low-temperature experiments on tunneling under pressure up to
3 GPa in a piston-cylinder gauge. Here we present the barrier height versu
s pressure for heavily doped n-GaAs(Te)/Au (N-e approximate to (5 - 7) x 10
(18) cm(-3)) tunnel junctions and compare the obtained pressure dependence
of the Schottky barrier with the known behavior of the band gap under press
ure taking into account the influence of the L- and X-valleys and DX center
s.