DX centers in InxAl1-xAs

The composition dependence of the energy levels of the DX centers in InxAl1 -xAs/InyGa1-yAs heterostructures have been determined by means of Hall effe ct and persistent photoconductivity measurements made on gated Hall bar tes t structures, primarily in the indirect portion of the fundamental band gap of InxAl1-xAs. The energy of the DX center relative to the average of the main conduction band minima of the Brillouin zone, in the composition range , 0.1 less than or equal to x less than or equal to 0.34, is E(DX)similar t o 0.3 eV; for x>0.4 the DX center is resonant with the conduction band. (C) 1999 American Institute of Physics. [S0021-8979(99)00206-6].