Example of a Compound Semiconductor Surface that Mimics Silicon: The InP(001)-(2×1) Reconstruction

An InP(001)- $(2\times 1)$ reconstruction was prepared by metal-organic vapor-phase epitaxy. Scanning tunneling micrographs and infrared spectra of adsorbed hydrogen revealed that the $(2\times 1)$ is terminated with a complete layer of buckled phosphorous dimers, giving rise to $p(2\times 2)$ and $c(4\times 2)$ domains. A surface band gap of $1.2\pm 0.2\mathrm{eV}$ was measured by scanning tunneling spectroscopy. The buckling can be explained by electron correlation among the dangling bonds of pairs of phosphorous dimers. This allows the surface to achieve a lower energy, semiconducting state. This reconstruction mimics the Si(100)- $(2\times 1)$, which is terminated with buckled silicon dimers.