On the origin of the semi-insulating behaviour of low-temperature In/sub 0.52/Al/sub 0.48/As grown by molecular beam epitaxy

We have investigated the origin of the semi-insulating (SI) behaviour of low-temperature In/sub 0.52/Al/sub 0.48/As by correlating electrical and structural properties of epilayers grown by MBE on InP in the 300/spl deg/C-565/spl deg/C temperature range. Using a statistical model, we have analysed the dependence of the Fermi level energy on measurement temperature (77 K-400 K) for SI layers. The resistivity and the transport properties appear to be controlled by three electron traps whose origin is discussed on the basis of extended and structural point defects as observed by TEM.