Deep levels in hafnium- and zirconium-doped indium phosphide

4d and 5d transition metals Zr and Hf were introduced into n-type InP using low-pressure–metal-organic chemical-vapor deposition up to the concentration of (1–3)×${10}^{17}$ ${\mathrm{cm}}^{\mathrm{-}3}$. The epilayers were investigated by deep-level transient spectroscopy with a view of searching for the deep levels associated with substitutional Hf and Zr, which are isovalent to Ti, a midgap deep donor in InP. In InP:Hf, three deep levels could be associated with Hf. Detailed emission rate, concentration profile, and capture cross-section measurements were undertaken for these three levels, HfA, HfB, and HfC, which were found to have energy positions ${\mathit{E}}_{\mathit{c}}$-0.51 eV, ${\mathit{E}}_{\mathit{c}}$-0.15 eV and ${\mathit{E}}_{\mathit{c}}$-0.12 eV, respectively. HfA was found to be a good candidate for the level associated with the isolated substitutional Hf in InP. The InP:Zr samples revealed two levels Zr1 and Zr2, with energy positions ${\mathit{E}}_{\mathit{c}}$-0.53 eV and ${\mathit{E}}_{\mathit{c}}$-0.10 eV, respectively, Zr1 being possibly the level due to the substitutional Zr.