Electronic properties of low-temperature InP

We have investigated InP layers grown by low-temperature (LT) gas source molecular beam epitaxy. Using high-pressure hall effect measurements, we have found that the electronic transport in the LT epilayers is determined by the presence of the dominant deep donor level which is resonant with the conduction band (CB) located 120 meV above the CB minimum (ECB). We find that its pressure derivative is 105 meV/GPa. This large pressure derivative reveals the highly localized character of the donor which via auto-ionization gives rise to the high free electron concentration n. From the deep level transient spectroscopy and Hall effect measurements, we find two other deep levels in the band gap at ECB−0.23 eV and ECB−0.53 eV. We assign the two levels at ECB 0.12 eV and ECB−0.23 eV to the first and second ionization stages of the phosphorus antisite defect.