Two local vibrational modes related to hydrogen in GaN

Abstract

We have observed two absorption bands located at around 1730 and 2960 cm−1 in the infrared (IR) absorption spectra from undoped GaN samples which are grown using low pressure metalorganic vapor phase epitaxy and irradiated by gamma ray and then exposed to a radio frequency hydrogen plasma. Proton implantation followed by gamma-ray irradiation of the GaN samples can also activate the IR band at around 1730 cm−1. Based on the experimental results, we tentatively ascribe the 1730 cm−1 band to the local vibrational modes of Ga–H complexes in the vicinity of N vacancies and the 2960 cm−1 band to those of either N–H complexes in the vicinity of Ga vacancies or C–H complexes.

Acceptor Neutralisation by Hydrogen in GaN and Wide Band Gap II-VI Materials

“…As a matter of fact, one paper [28] is devoted to this observation, but the spectra presented look too much like those of hydrocarbons such as pump oil for instance for being credible. The same type of spectra has also been reported in [29]. One explanation for the absence of observation of a credible LVM associated with a carbon-hydrogen complex could have been that the H related bond of the complex is along the c-axis (type I complex) and therefore its observation would not have been possible with the``conventionalº set-ups in which the wave vector of the light is along the c-axis.…”