AVS 50th International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM5
Indium Phosphide (001)-(2x1): Evidence for a Hydrogen-Stabilized Surface Reconstruction

Wednesday, November 5, 2003, 9:40 am, Room 328

Session: Adsorption on Semiconductor Surfaces
Presenter: G. Chen, University of California, Los Angeles
Authors: G. Chen, University of California, Los Angeles
D. Cheng, University of California, Los Angeles
D. Tobin, University of California, Los Angeles
Y. Sun, University of California, Los Angeles
K. Raghavachari, Indiana University
R.F. Hicks, University of California, Los Angeles
Correspondent: Click to Email
Metalorganic vapor-phase epitaxy (MOVPE) is widely used to produce InP-based optoelectronic devices. Deposition of InP (001) films occurs in a large excess of the group V precursors, resulting in the formation of a P-rich (2x1) reconstruction. Scanning tunneling microscopy indicates that the (2x1) is terminated with a complete layer of buckled phosphorus dimers. This structure has been the subject of debate, because it should violate the electron counting model and exhibit partially filled P dangling bonds. In this work, we report on a vibrational study of the (2x1) surface prepared in the MOVPE environment. Infrared spectra collected during deuterium titration reveals the presence of a single sharp P-H stretching mode at 2308 cm^-1. Based on theoretical cluster calculations using density functional theory, this mode results from a single hydrogen atom bonded to one end of the buckled phosphorus dimer. This structure does not violate the electron counting model. In addition, slab calculations by another research group indicate that hydrogen-termination of the P dimers should yield the most stable configuration for the (2x1). Therefore, it may be concluded that adsorbed hydrogen atoms stabilize the phosphorus-rich surface structure during indium phosphide film growth by MOVPE.