InP has the potential to be an extremely important III-V semiconductor material for high speed electronic devices. It has both a higher mobility and thermal conductivity than GaAs [51], making it suitable for high-speed switching circuits, and its direct band gap makes it highly suitable for optoelectronic devices such as field-effect transistors. It also has great potential for use in single-junction photovoltaic cells, as its energy gap is close to that required for optimum solar radiation to electricity conversion [52]. It is also relatively radiation resistant making it suitable for solar cell use in space.
Trace impurities can lead to a deterioration in the electrical properties of InP when such impurities are electrically active. For this reason there has been recent interest in the possibility of passivating these residual impurities using hydrogen [53,54]. Hydrogen is also routinely used during technological processing of InP. A hydrogen plasma is used during the fabrication of high-speed InP-based devices and methane is used during reactive ion etching [55]. For all of these reasons, a detailed understanding of hydrogen related defects in InP is required.