ULTRA-LOW TEMPERATURE OMVPE OF INAS AND INASBI

InAs and InAsBi have been grown by atmospheric pressure organometallic vapor phase epitaxy (OMVPE) over a broad temperature range from 600 to as low as 275-degrees-C. This is the lowest growth temperature ever reported for conventional OMVPE. It is demonstrated that lowering the growth temperature is the most effective approach for increasing the maximum Bi content in InAsBi alloys where the Bi solubility limit is 0.025 at.%. For example, InAsBi samples with Bi concentrations as high as 6.1 at.% have been successfully grown at a temperature of 275-degrees-C. trimethylindium, arsine, and trimethylbismuth were used as precursors for most experiments. The growth efficiency is a constant for temperatures above 400-degrees-C, indicating that the growth rate is diffusion limited. For lower temperatures, it decreases exponentially with decreasing temperature with an activation energy of 24 kcal/mol. Incomplete pyrolysis of TMIn limits the growth rate in this temperature regime. By substituting ethyldimethylindium for TMIn the growth rate can be increased at lower temperatures. Hall effect measurements show that the n-type background concentration increases from approximately 2.3 x 10(16) to 10(19) cm-3 as the growth temperature decreases from 600 to 325-degrees-C. Secondary ion mass spectroscopy results show that the dominant impurity is carbon. Thus, carbon is mainly a donor in these materials. The integrated photoluminescence intensity drops rapidly with decreasing growth temperature.