Thermoelectric effect spectroscopy of deep levels—application to semi-insulating GaAs

A new method, thermoelectric effect spectroscopy, is proposed for the analysis of deep levels in semi-insulating materials. Besides the information on energy position and relative concentrations of traps, the main advantage of the method is its ability to determine the trap sign, i.e., the method is capable to resolve electron traps from hole traps. The proposed method is very simple for application. It is also shown how in combination with other techniques it can give a complete picture about trap-filling dynamics during low-temperature transient phenomena caused by illumination. The applicability and validity of the method are demonstrated on GaAs in which both electrons and hole traps are found.