The solution chemistry and kinetic behavior of hafnium peroxy sulfate solutions ("HafSOx") is described in terms of peroxide content and solution speciation. Additionally, thin film behavior, including thermal behavior and solubility, is characterized, and a mechanism of patterning is presented, as well as parameters that should be considered when looking...
The subject of this PhD thesis is part of a research domain of great present interest in new semiconductor materials for photovoltaic and thermoelectric applications. This domain contains the elaboration and the study of both Cu-based chalcogenides bulk and thin-film samples, driven by materials design principles.
One of the most...
A new approach to the discovery of high absorbing semiconductors for solar cells was taken by working under a set of design principles and taking a systemic methodology. Three transition metal chalcogenides at varying states of development were evaluated within this framework. Iron pyrite (FeS₂) is well known to demonstrate...
The use of an adjacency matrix to determine distant (not maximal or
minimal) subgroup and supergroup relationships between crystallographic spacegroup
types is described. Full lists of space-group types that are supergroups and
subgroups for every space-group type were compiled. A list of the space-group
types connected to each space-group type...
The materials Fe₂(Si,Ge)(S,Se)₄, Cu₃PS[subscript 4-x]Se[subscript x] (0 ≤ x ≤ 4), and Cu₃PxAs[subscript 1-x]S₄ (0 ≤ x ≤ 1) have been synthesized and studied as new earth-abundant absorbers for single and multijunction photovoltaic cells as well as solar fuel generation. The synthesis, single-crystal growth, and optical and electrical properties of...
The chemistry of hafnium oxide based and materials are described in the context of ion exchange and lithography. HafSOx, represented by the composition HfO₂₋[subscript x](SO₄)x, is described to possess a significant capacity towards ion exchange in acidic and basic solutions, enabling films of HafSOx to be cleanly and readily be...
New transparent p- and n-type semiconductors and luminescent materials have been prepared and characterized. Synthesis, structures, optical and electrical properties of new chalcogenide fluoride p-type transparent semiconductors MCuQF (M=Ba, Sr; Q=S, Se, Te) are described. Band-gap tuning and improvement in conductivity through p-type doping are demonstrated in the family. The...
The aqueous chemistries of two transition metal cations, Zr⁴⁺ and Nb⁵⁺, are examined and then used to develop inorganic precursor solutions. The oxides of these cations (ZrO₂ and Nb₂O₅) are deposited and characterized, and their morphological and optical properties discussed. Due to the obstacles created by niobium's aqueous chemistry, an...
Crystals of an incongruent-melting compound, Ba₃MgSi₂O₈, were grown by the flux method and its structure was determined by single crystal X-ray diffraction methods. Ba₃MgSi₂O₈ crystallizes in trigonal space group P-3[bar]m1 with a = 5.6123(3) Å, c = 7.2667(9) Å and Z = 1. Eu²⁺ ions prefer one crystallographic Ba site...
This dissertation outlines two approaches for improving the efficiency and reducing the cost of photovoltaic energy generation. First, the structures of known binary copper and iron compounds are used to choose the promising compositions Fe₂XS₄ (X = Si, Ge), Cu₃TaQ₄ (Q = Se, Te), and BaCuQ'F (Q' = S, Se,...