Semi‐insulating properties of Fe‐implanted InP. II. Deep levels of Fe from the study ofp+‐semi‐insulating‐n+diodes

The properties of semi‐insulating (SI) Fe‐implanted InP are studied via the electrical and optical properties of p+‐SI‐n+ InP diodes. The current‐voltage‐temperature characteristics reveal a rich variety of transport processes in which the deep levels of Fe play a prominent role, including tunneling and field‐assisted thermionic emission from these levels, and space‐charge‐limited double‐injection current effects. From the analysis of these currents, different experimental estimates of the position of the deep levels have been obtained. These are compared with a direct experimental determination of their position from the measurement of the photocurrent spectra of the p+‐SI‐n+ diodes. These results establish the position of the iron acceptors at a level lying between 0.60–0.65 eV below the conduction band minimum. Capacitance spectroscopy of the p+‐SI‐n+ diodes revealed additional defect levels and carrier freeze‐out effects at low temperatures.