Measurement of deep intrinsic defects in thin ZnO films via mid‐infrared photocurrent spectroscopy

ZnO thin films are investigated by the electrical method of deep level transient spectroscopy (DLTS) and by the optical method of Fourier transform infrared photocurrent (FTIR‐PC) spectroscopy. FTIR‐PC spectra show several well‐resolved peaks between 100 meV and 400 meV. They include the commonly observed defects E1 at ∼120 meV and E3 at ∼320 meV caused by transitions from deep donor‐like states to the conduction band. The impact of annealing either in vacuum or in oxygen or nitrogen atmospheres is investigated.