Atomic structure and optoelectronic properties of In0.53Ga0.47As (100) reconstruction surfaces: A DFT study

There are kinds of reconstructions on InGaAs(100) surface, such as As-rich β2(2 × 4), In-rich α(2 × 4), and Ga-rich α(2 × 4) reconstructions. In this article, the three kinds of In0.53Ga0.47As(100) reconstruction surfaces are studied based on first-principles calculations, and atomic structures, formation energies, band structures, electron distributions, and absorption coefficients were obtained. Atomic structures of the surfaces were calculated and results show that the relaxation of As-rich β2(2 × 4) surface is the smallest. The As-rich β2(2 × 4) surface also has the smallest formation energy, which means the As-rich β2(2 × 4) surface is the steadiest among the three surfaces. Furthermore, the energy band structures and the work function are analyzed. The less the work function is, the easier the photoelectrons escape from the surfaces. Therefore, it is the easiest for photoelectrons to escape from As-rich β2(2 × 4) surface due to its lowest work function. The same conclusion is also confirmed based on the calculations of the electronic structure. The negative electron affinity photocathode is mainly sensitive to the infrared region where the absorption coefficient of the As-rich β2(2 × 4) surface is bigger than those of the In-rich α(2 × 4) and Ga-rich α(2 × 4) surfaces. The As-rich β2(2 × 4) surface is benefit for the formation of the negative electron affinity In0.53Ga0.47As photocathode.