Barrier roughness effects in resonant interband tunnel diodes

Peak current densities of InAs/AlSb/GaSb/AlSb/InAs resonant interband tunne ling diodes (RITD) grown by molecular beam epitaxy have been measured as a function of the growth temperature. The growth procedures were designed to produce nominally identical AlSb tunneling barriers. The variations observe d in the peak current for positive bias are consistent with the barrier on the substrate side of the RITD becoming effectively thicker for diodes grow n at high temperatures. Plan-view in situ scanning tunneling microscopy (ST M) measurements indicate that smoother AlSb barriers are grown at high temp erature. The growth temperature dependence of the peak current density and STM results are consistent, because tunneling is highly dependent on barrie r thickness. While the high and low temperature growths were designed to ha ve the same barrier thickness, the large current flowing through the thin a reas of a rough barrier result in an effectively thinner barrier compared t o the smooth one. (C) 2001 American Institute of Physics.