MOMBE growth of heavily carbon-doped n-type InP using tertiarybutylphosphine (TBP)

Heavily carbon-doped n-type InP was grown by metalorganic molecular beam epitaxy (MOMBE) using elemental In and tertiarybutylphosphine (TBP). In this study, TBP was employed as both phosphorus and carbon source, and carbon-doping characteristics in MOMBE growth of InP using TBP were discussed for the first time. The electron concentration of carbon-doped InP could be controlled in three orders of magnitude (n=10¹⁶~10¹⁹ cm^-3) by varying the growth temperature and TBP cracking temperature. As the TBP cracking temperature increases, electron concentration was increased and also showed less dependence on growth temperature. This indicates that the overall carbon incorporation in InP may be dominated by the more atomic-like carbon-containing species of the cracked TBP. In addition, the lattice location of carbon impurity atom in InP was estimated for the first time by the observation of a gap mode using Raman scattering spectroscopy. The observed peak at 225 cm^-1 corresponds to a gap mode due to carbon impurity substituted on In lattice site in InP and shows a good agreement with the theoretical value. This is direct evidence that carbon from TBP is incorporated on In lattice site and acts as a donor in InP