Photoelectrochemical (PEC) water splitting is a promising approach for synthesizing chemical fuels from sunlight. First demonstrated by Fujishima and Honda in 1972, PEC cell components and design strategies have proliferated in recent years. Regardless of the specific device architecture, however, any efficient PEC device requires (1) a high yield of energetic photogenerated carriers and (2) a mechanism for extracting these photogenerated carriers, (3) a corrosion-resistant anode at the pH and operating potential of the device, and (4) an effective catalyst for water oxidation. This dissertation addresses these challenges in the context of a photoanode, where water oxidation is tightly coupled to one of the light-absorbing elements of the PEC device. Metal-insulator-semiconductor (MIS) junctions are a promising photoanode design that electronically couples a high-quality semiconductor to an efficient water oxidation catalyst. The photovoltage produced by an MIS junction depends on the strength of the built-in field, or Schottky barrier height. This built-in field, in turn, depends on the difference in work function between the semiconductor and the metal, taking charges and interface fields into account. For optimal performance, a high work function metal induces a field that sweeps photogenerated holes from an n-type semiconductor to the electrolyte interface for water oxidation. In addition to generating large photovoltages, the ideal Schottky contact to an n-type semiconductor photoanode must also catalyze water oxidation and protect the underlying semiconductor from corrosion. In this work, I use atomic layer deposition (ALD) to fabricate alloys of TiO2 and transition metal oxides (specifically RuOx and IrOx) that function as the "M" of an MIS photoanode. Alloying TiO2 with these noble metal oxides combines the corrosion resistance of TiO2 with the high work function and catalytic activity of RuOx and IrOx. These alloys represent an ultra-thin analogue to the dimensionally stable anode used industrially for chlorine evolution. By investigating the chemical and electronic properties of these alloys, I unravel some of the key design principles for corrosion resistant Schottky contacts in MIS photoanodes. First, I demonstrated that ALD TiO2 protects the underlying silicon from corrosion and stabilizes RuOx and IrOx during water oxidation in acid. Second, I found that the electronic properties of TiO2 could be altered by alloying with metal oxides that have the desired work function. TiO2 makes a poor Schottky contact to n-type silicon, and its conductivity is difficult to control. Alloying TiO2 with high work function, conductive metal oxides like RuOx or IrOx not only enables high photovoltages but also guarantees high conductivity. By comparing the electronic properties of TiO2-RuOx alloys with TiO2-IrOx alloys, I also determined that the density of states at the alloy/SiO2 interface was critical for charge transport through the MIS junction. Finally, I gained insight into the relationship between catalytic activity and stability for RuOx and IrOx, two of the most commonly used water oxidation catalysts in acid. While IrOx is more stable than RuOx, its catalytic activity nonetheless degrades slowly over time. Though I used silicon as a model semiconductor, this ALD alloying approach may be particularly valuable for semiconductors that must rely on MIS junctions to generate large photovoltages (because forming a p-n junction is problematic). ALD enables unusually precise control over both the film thickness and composition. The ability to create graded structures by ALD presents a unique opportunity to control the composition these protection layers as a function of depth, placing valuable metal atoms where they are needed most—at the electrode/electrolyte interface for catalysis and at the insulator/metal interface for efficient tunneling. As such, ALD is capable of addressing many of the challenges associated with fabricating carrier selective contacts in photoelectrochemical and photovoltaic devices.

The Springer Reference Work Handbook of Manufacturing Engineering and Technology provides overviews and in-depth and authoritative analyses on the basic and cutting-edge manufacturing technologies and sciences across a broad spectrum of areas. These topics are commonly encountered in industries as well as in academia. Manufacturing engineering curricula across universities are now essential topics covered in major universities worldwide.

This book guides beginners in the areas of thin film preparation, characterization, and device making, while providing insight into these areas for experts. As chemically deposited metal oxides are currently gaining attention in development of devices such as solar cells, supercapacitors, batteries, sensors, etc., the book illustrates how the chemical deposition route is emerging as a relatively inexpensive, simple, and convenient solution for large area deposition. The advancement in the nanostructured materials for the development of devices is fully discussed.

This book describes the rapidly expanding field of two-dimensional (2D) transition metal carbides and nitrides (MXenes). It covers fundamental knowledge on synthesis, structure, and properties of these new materials, and a description of their processing, scale-up and emerging applications. The ways in which the quickly expanding family of MXenes can outperform other novel nanomaterials in a variety of applications, spanning from energy storage and conversion to electronics; from water science to transportation; and in defense and medical applications, are discussed in detail.

Photoelectrochemical Hydrogen Production describes the principles and materials challenges for the conversion of sunlight into hydrogen through water splitting at a semiconducting electrode. Readers will find an analysis of the solid state properties and materials requirements for semiconducting photo-electrodes, a detailed description of the semiconductor/electrolyte interface, in addition to the photo-electrochemical (PEC) cell. Experimental techniques to investigate both materials and PEC device performance are outlined, followed by an overview of the current state-of-the-art in PEC materials and devices, and combinatorial approaches towards the development of new materials. Finally, the economic and business perspectives of PEC devices are discussed, and promising future directions indicated. Photoelectrochemical Hydrogen Production is a one-stop resource for scientists, students and R&D practitioners starting in this field, providing both the theoretical background as well as useful practical information on photoelectrochemical measurement techniques. Experts in the field benefit from the chapters on current state-of-the-art materials/devices and future directions.

Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (due to the systematic presentation of the results at the forefront of the technique and their applications) and the ones of students and newcomers to the fi eld (through the first part detailing the basic aspects of the technique). This book is a must-have for all Materials Scientists, Surface Chemists, Physicists, and Scientists in the Semiconductor Industry.

Transparent conducting materials are key elements in a wide variety of current technologies including flat panel displays, photovoltaics, organic, low-e windows and electrochromics. The needs for new and improved materials is pressing, because the existing materials do not have the performance levels to meet the ever- increasing demand, and because some of the current materials used may not be viable in the future. In addition, the field of transparent conductors has gone through dramatic changes in the last 5-7 years with new materials being identified, new applications and new people in the field. “Handbook of Transparent Conductors” presents transparent conductors in a historical perspective, provides current applications as well as insights into the future of the devices. It is a comprehensive reference, and represents the most current resource on the subject.