DEEP LEVELS AND A POSSIBLE D-X-LIKE CENTER IN MOLECULAR-BEAM EPITAXIAL INXAL1-XAS

Dominant deep electron and hole traps in lattice-matched In//0//. //5//2Al//0//. //4//8As/InP grown by molecular beam epitaxy have been identified and characterized. The traps have activation energies ranging from 0. 25 to 0. 95 eV. The electron traps have very large capture cross-sections, approximately 10** minus **1**2 minus 10** minus **1**1 cm**2, similar to attractive centers. The lattice-matched samples do not show any persistent photoconductivity effects at low temperatures. In strained In//1// minus //xAl//xAs with 0. 48 less than x less than equivalent to 0. 57, an electron trap with a thermal ionization energy of 0. 35 eV, a strong dependence of its concentration on donor doping and very small thermal capture cross-section, 10** minus **1**8 cm** minus **2, is identified. These samples exhibit persistent photoconductivity. We believe this trap is similar to the D-X center commonly observed in Al//xGa//1// minus //xAs for x greater than equivalent to 0. 28.