Deep levels in low resistive Zn3P2

Abstract

The low resistivity p‐type polycrystalline Zn3P2 grown by means of closed tube vapor transport was investigated. Deep carrier traps have been studied by means of deep level transient spectroscopy (DLTS) and by photocapacitance transient measurements. From DLTS measurements parameters of four main hole traps were determined. The first with activation energy 0.17 eV above the top of the valence band, probably connected with zinc vacancy, the defect with activation energy 0.34 eV which origin is unknown, the defect with activation energy 0.46 eV, probably oxygen related and the defect with activation energy 0.77 eV with unknown origin. For the defects with energies 0.17 and 0.46 eV nonzero values of capture energies were found: 0.03 and 0.16 eV, respectively. From photocapacitance measurements three optical activation energies were determined as steps on the curve: 0.83, 0.99, and 1.25 eV. Defects with optical activation energies of 0.83 eV is probably the same defect as defect with activation energy 0.46 eV and energy barrier for capture 0.16 eV obtained from DLTS measurements, and may be responsible for persistent photoconductivity (PPC) efect in high resistive samples of Zn3P2.