INASBI ALLOYS GROWN BY ORGANOMETALLIC VAPOR-PHASE EPITAXY

InAsBi is a III/V alloy with potential application for detectors in the 8-12 mum region of the spectrum. Growth of InAs1-xBix, with x less-than-or-equal-to 0.054, at 350-degrees-C by atmospheric pressure organometallic vapor phase epitaxy has been made possible by using a new combination of precursors, ethyldimethylindium (EDMIn), tertiarybutylarsine (TBAs) and trimethylbismuth (TMBi). Results were obtained using a V/III ratio between 21 and 22. With these conditions, a Bi distribution coefficient of 1.746 was measured. X-ray diffraction verifies that Bi incorporates substitutionally into the zincblende structure. For x < 0.045, it was possible to suppress whisker formation and obtain excellent surface morphology. Measurement of photoluminescence for x less-than-or-equal-to 0.037 indicates good crystal quality. The measured rate of change of bandgap with Bi concentration, dE(g)/dx = -55 meV/%Bi, indicates that a 77 K bandgap energy of E = 0.10 eV should be reached with an alloy composition of InAs0.94Bi0.06.