Thermoelectric voltage spectroscopy for studying compensation in semi-insulating wide energy band gap materials

A new method, thermoelectric voltage spectroscopy (TEVS), is demonstrated f or the study of deep levels and compensation. Thermally stimulated conducti vity (TSC) and thermoelectric emission spectroscopy (TEES) results are also shown for comparison. In TEVS, the thermoelectric voltage across a sample is measured as a function of the temperature, during the thermal stimulatio n of electron and hole traps. The TEVS voltage shows steps that reflect (1) the change of the electron and hole quasi-Fermi levels due to detrapping a nd (2) the trap type, whether electron or hole. A simple product rule holds between the TEVS voltage, TSC current, and TEES current, when identical tr ap filling and heating are done. The combination of TSC and TEVS is a power ful way for studying compensation and deep levels in semi-insulating wide e nergy band gap materials. (C) 1999 Elsevier Science Ltd. All rights reserve d.