Traps in undoped semi‐insulating InP obtained by high temperature annealing

The presence and evolution of traps in undoped semi‐insulating (SI) InP obtained by high temperature annealing (900 °C for 90 h) in poor or rich phosphorus atmosphere has been studied by means of photoinduced current transient spectroscopy. Six traps named A1 to A6 having activation energies ranging from 0.2 to 0.6 eV have been detected in three samples submitted to the same annealing process. The samples differ in the Fe concentration of the starting material and the applied phosphorus pressure in the annealing process. A comparison of the corresponding photoinduced current transient spectroscopy spectra shows that among the observed traps, the 0.2 eV one can be related to a phosphorus deficiency, and the 0.3 eV and 0.4 eV traps could be due to an excess of phosphorus during annealing. Moreover, the trap corresponding to iron (0.6 eV) has been observed in all the studied samples.