Three growth-temperature-dependent regions for nitrogen incorporation in GaNAs grown by chemical beam epitaxy

The effects of growth temperature on nitrogen incorporation in GaNAs grown by chemical beam epitaxy are studied from 340 to 515°C. Generally speaking, with increasing growth temperature, nitrogen content decreases. However, three distinct growth-temperature-dependent regions for nitrogen incorporation with activation energies of 0.59, 0.05, and 0.95 eV can be identified at low, middle, and high growth temperatures, respectively. At low and high growth temperatures, the growth temperature dependences of nitrogen incorporation are due to triethylgallium (TEG)-pyrolysis- and nitrogen-desorption-controlled processes, respectively, while a TEG-transportation-limited process is observed at middle temperatures. Atomic force microscope (AFM) results also show that there are three different surface morphologies for GaNAs grown at different growth temperatures. Based on X-ray diffraction (XRD) and AFM results, the best growth mechanism is determined, and high quality GaN_0.007As _0.993/GaAs triple quantum wells are obtained.