Electrical Measurement Under Atmospheric Conditions of PbSe Nanocrystal Thin Films Passivated by Remote Plasma Atomic Layer Deposition of Al2O3

PbSe nanocrystal thin-film transistors (TFTs) were passivated using remote plasma atomic layer deposition (ALD) of a similar to 10 nm thick Al2O3 film at 150 degrees C. By using a highly reactive remote oxygen plasma source, the time for one complete ALD cycle was about 15 s with growth rates of similar to 1.1 angstrom/cycle. The effective mobilities measured under atmospheric condition from Al2O3-passivated PbSe nanocrystal TFTs were comparable to the values reported previously for air-free PbSe nanocrystal TFTs, demonstrating that ALD Al2O3 layers prevent oxidation and degradation of nanocrystal films from air exposure. The variation in the effective mobility of passivated devices was also found to be negligible under ambient conditions over a period of 30 days. The results show that remote plasma ALD processing of Al2O3 is capable of producing an effective passivation layer on air-sensitive nanocrystals with high deposition rates at reduced temperature.