ELECTRONIC-PROPERTIES OF LOW-TEMPERATURE INP

We have investigated InP layers grown by low-temperature (LT) gas sour ce molecular beam epitaxy. Using high-pressure Hall effect measurement s, we have found that the electronic transport in the LT epilayers is determined by the presence of the dominant deep donor level which is r esonant with the conduction band (CB) located 120 meV above the CB min imum (E(CB)). We find that its pressure derivative is 105 meV/GPa. Thi s large pressure derivative reveals the highly localized character of the donor which via auto-ionization gives rise to the high free electr on concentration n. From the deep level transient spectroscopy and Hal l effect measurements, we find two other deep levels in the band gap a t E(CB) - 0.23 eV and E(CB) - 0.53 eV. We assign the two levels at E(C B) + 0.12 eV and E(CB) - 0.23 eV to the first and second ionization st ages of the phosphorus antisite defect.