Photocapacitance effects of deep traps in n-type InP

Abstract

Deep trapping centers in n‐type InP samples grown by the liquid‐encapsulated Czochralski, liquid‐phase‐epitaxial, and vapor‐phase‐epitaxial processes have been studied by photocapacitance techniques. Photocapacitance effects for Schottky barriers formed on these samples indicate four levels at 0.58, 0.78, 0.89, and 1.15 eV below the conduction band. Estimated trap concentration in various samples range from low‐10¹⁴ cm⁻³ to the high‐10¹² cm⁻³. The broad increase in photocapacitance near 1.15 eV for all the samples may be associated with an intrinsic defect or phosphorus vacancy/impurity complexes. This result is consistent with the broadband present between 1.08 and 1.25 eV in photoluminescence experiments. The comparison between O₂‐doped and undoped VPE samples suggests the presence of oxygen located at about 0.78 eV below the conduction band in VPE material.