Electrical and FT-IR measurements of undoped n-type InP materials grown from various stoichiometric melts

P-rich, In-rich and stoichiometric undoped InP melts have been synthesised by phosphorus in-situ injection method. InP crystal ingots have been grown from these melts by the liquid encapsulated Czochralski method (LEC). Samples from these ingots grown from various stoichiometric melts have been characterized by Hall effect and Fourier Transform Infrared (FT-IR) spectroscopy measurements respectively. The Hall effect measurement results indicate that the net carrier concentration of P-rich undoped InP is higher than that of In-rich and stoichiometric undoped InP materials. FT-IR spectroscopy measurements reveal that there are intensive absorption peaks which have been due to a hydrogen related indium vacancy complex V_InH₄. By comparing FT-IR spectra, it is found that P-rich InP material has the most intensive absorption peak of V_lnH₄, while In-rich InP material has the weakest absorption peak