The removal of decomposition to N2 changes the phase diagrams significantly as expected. For AlN, Figure , the main surface structures are still NH2(tp), H(tp) and bare sites with the addition of NH2(br) at intermediate temperatures. At low temperatures NH2(tp) still dominates the surface coverage up to 890 K where NH2(br) appears. Bare sites start to appear at higher temperatures as the nitrogen from NH3 cannot desorb as nitrogen gas, causing more sites to be occupied. At the highest temperatures however, bare sites start to dominate, and the surface becomes uncovered. As less NH3 decomposes there is less free hydrogen present in the system, which leads to the H(tp)-containing phases to only appear in a small area of high temperature and pressure. Other minor species that appear are the N2H2(ho) and NH(ho) who reach their maximum below 0.1 % coverage at intermediate temperatures, Figure . For InN the phase diagram, Figure , without NH3 decomposition exhibits fewer phases compared to those of AlN and GaN, as in the case with NH3 decomposition included (Figure ). At low temperatures, the surface is covered by a mixture of NH2(tp) and bare sites. There is a region at high pressure and low temperature where NH2(br) also reaches above the threshold. The NH2(tp) is stable up to slightly higher temperatures compared to if decomposition was allowed, until bare sites become the only stable structure. The two most abundant minor structures were the two N2H2 dimers with a maximum of around 0.1-0.2 % at around 600 K, Figure .