Structural, Electrical and Optical Characterization of Thiol Treated PbTe Thin Films Infilled by Alumina ALD
PbTe quantum dots have demonstrated material handling difficulties arising due to its high reactivity which leads to poor stability, synthetic yields and electronic characteristics. These problems arise even in glovebox environments, where aggressive surface oxidation degrades the material and contribute to the p-channel behavior of thiol treated field effect transistors (FET) which are characterized by low FET mobilities, high carrier concentrations and non-gateable devices. The high reactivity limits the use of typical nucleation assisting precursors which improve nanocrystal formation in PbSe and PbS, but unfortunately lead to rapid, uncontrolled growth of PbTe nanocrystals. The application of ALD (atomic layer deposition) to PbTe films creates new opportunities for study. It scavenges and passivates surface states and some surface oxides that have formed during the ligand exchange and allows the creation of gateable n-channel FET devices with electron mobilities of ~1cm2/V s and indefinite stability. The poor stability was substantiated through comparison with PbSe quantum dots using UV-Vis spectroscopy. This thesis will discuss the general theory of quantum dots and initial work on PbTe field effect transistors treated with thiols and infilled with alumina atomic layer deposition.