Electrical characterization of semi-insulating InAlAs grown by molecular beam epitaxy.

Current-voltage measurements on undoped InAlAs layers grown by MBE are reported. The resistivities were found to be 1. 2 x 10 sup 8, 8 x 10 sup 7 and 7 x 10 sup 7 OMEGA-cm for the three samples that were investigated. The results indicate that these undoped InAlAs layers are highly semi-insulating, and that such layers grown in our MBE system have potential use as electrical isolation layers in laser and FET device structures. The activation energies of layers were calculated to be 0.75 +- 0.01 eV from the temperature dependence of the resistance, which is about half the value of the InAlAs energy bandgap. We conclude that the deep level responsible for the semi-insulating nature of the layer is a midgap level.