Group V adsorbate structures on vicinal Ge(001) surfaces determined from the optical spectrum

Abstract

Vicinal Ge(001) is the standard substrate for the fabrication of high-performance solar cells by metal-organic vapour phase epitaxy, where growth of the III-V material on single domain Ge surfaces, with a single dimer orientation, minimizes the formation of anti-phase domain defects. Reflectance anisotropy spectroscopy has proved to be a powerful and sensitive optical probe of such anisotropic surface structures, but moving beyond fingerprinting to atomic structure determination from the optical spectra has been held back by the high computational cost. It is shown that an empirical, local-orbital-based hybrid density functional theory approach produces very good agreement between the theory and the experiment for (2 × 1)-As and (2 × 1)-Sb structures grown on vicinal Ge(001). These results, when taken together with previous work on Si interfaces, show that this computationally efficient approach is likely to prove to be an important general technique for determining the structure of anisotropic semiconductor surfaces and interfaces by comparing the experimental and calculated optical spectrum.

Surface Reactions of Atomic Hydrogen with Ge(100) in Comparison with Si(100)

“…On the other hand, much less research attention has been paid to the surface chemistry of H(g) on Ge(100) compared with Si(100) [15][16][17][18][19]. While germanium attracts renewed attention in view of the next-generation semiconductor technology due to its high carrier mobility [20][21][22][23][24][25][26][27][28][29][30], we decided to perform a comparative study on the H(g)/ Ge(100) system. Compared with c-Si, c-Ge has a larger lattice constant and a weaker Ge-Ge bond on average.…”