Corinne E. Packard
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Planarizing Spalled GaAs(100) Surfaces by MOVPE Growth Open
III–V photovoltaic devices have demonstrated exceptional\nperformance across various applications, with controlled crystal fracturing,\nknown as controlled spalling, emerging as a promising method to reduce\ncosts by enabling substrate reu…
View article: In Situ Smoothing of Facets on Spalled GaAs(100) Substrates during OMVPE Growth of III–V Epilayers, Solar Cells, and Other Devices: The Impact of Surface Impurities/Dopants
In Situ Smoothing of Facets on Spalled GaAs(100) Substrates during OMVPE Growth of III–V Epilayers, Solar Cells, and Other Devices: The Impact of Surface Impurities/Dopants Open
One possible pathway toward reducing the cost of III-V solar cells is to remove them from their growth substrate by spalling fracture, and then reuse the substrate for the growth of multiple cells. Here we consider the growth of III-V cell…
Uncovering the Effects of Non-Hydrostaticity on Pressure-Induced Phase Transformation in Xenotime-Structured TbPO4 Open
The pressure-induced phase transformations of rare earth orthophosphates (REPO4s) have become increasingly relevant in ceramic matrix composite (CMC) research; however, understanding of the shear-dependence of these transformations remains…
View article: 24% Single‐Junction GaAs Solar Cell Grown Directly on Growth‐Planarized Facets Using Hydride Vapor Phase Epitaxy
24% Single‐Junction GaAs Solar Cell Grown Directly on Growth‐Planarized Facets Using Hydride Vapor Phase Epitaxy Open
A 24%‐efficient single‐junction GaAs solar cell grown directly on a faceted, spalled (100) GaAs substrate after in situ planarization growth by hydride vapor phase epitaxy (HVPE) is achieved. Controlled spalling, a promising low‐cost subst…
View article: Publisher’s Note: “Light-trapping structures fabricated <i>in situ</i> for ultrathin III-V solar cells” [J. Appl. Phys. 134, 135307 (2023)]
Publisher’s Note: “Light-trapping structures fabricated <i>in situ</i> for ultrathin III-V solar cells” [J. Appl. Phys. 134, 135307 (2023)] Open
On page 3, the second paragraph, the first sentence has been corrected as "Textured morphologies were imaged with a JEOL JSM-7000F7 field emission SEM."On page 6, the last paragraph, the second sentence has been corrected as "Fig.3 shows t…
View article: Light-trapping structures fabricated <i>in situ</i> for ultrathin III-V solar cells
Light-trapping structures fabricated <i>in situ</i> for ultrathin III-V solar cells Open
Here, we describe a fully in situ method of fabricating light-scattering structures on III-V materials that generates a rough morphology via vapor phase etching and redeposition. Fully in situ methods support higher industrial throughput b…
Analysis of Crystalline Defects Caused by Growth on Partially Planarized Spalled (100) GaAs Substrates Open
We analyze the effect of growth on non-(100) surfaces resulting from incomplete planarization of spalled GaAs wafers on the defect structure of GaAs solar cell layers grown by hydride vapor phase epitaxy (HVPE). Controlled spalling of (100…
View article: Phase Transformation Pathway of DyPO4 to 21.5 GPa
Phase Transformation Pathway of DyPO4 to 21.5 GPa Open
Interest in the deformation behavior and phase transformations of rare earth orthophosphates (REPO4s) spans several fields of science—from geological impact analysis to ceramic matrix composite engineering. In this study, the phase behavio…
Design of Planarizing Growth Conditions on Unpolished and Faceted (100)-Oriented GaAs Substrates Using Hydride Vapor Phase Epitaxy Open
Here we performed a design of experiments (DoE) analysis to determine the effect of various growth parameters on in situ planarizing overgrowth of rough substrates using hydride vapor phase epitaxy (HVPE). We used two types of rough (100)-…
View article: High‐Efficiency Solar Cells Grown on Spalled Germanium for Substrate Reuse without Polishing
High‐Efficiency Solar Cells Grown on Spalled Germanium for Substrate Reuse without Polishing Open
Radical reduction of III–V device costs requires a multifaceted approach attacking both growth and substrate costs. Implementing device removal and substrate reuse provides an opportunity for substrate cost reduction. Controlled spalling a…
(110)-Oriented GaAs Devices and Spalling as a Platform for Low-Cost III-V Photovoltaics Open
Here, we demonstrate the growth of GaAs solar cells by hydride vapor phase epitaxy (HVPE) on epi-ready and previously spalled (110) GaAs wafers as an advance towards a potentially low-cost (110)-based device platform. Controlled spalling o…
View article: Discovering exceptionally hard and wear-resistant metallic glasses by combining machine-learning with high throughput experimentation
Discovering exceptionally hard and wear-resistant metallic glasses by combining machine-learning with high throughput experimentation Open
Lack of crystalline order in amorphous alloys, commonly called metallic glasses (MGs), tends to make them harder and more wear-resistant than their crystalline counterparts. However, finding inexpensive MGs is daunting; finding one with en…
Performance of III–V Solar Cells Grown on Reformed Mesoporous Ge Templates Open
We demonstrate a solar cell on reformed porous Ge with an efficiency of 7.7%. We generate mesopores in (100) Ge by bipolar electrochemical etching and anneal them at high temperature. The pores coalesce deep in the structure rather than at…
Inverted metamorphic GaInAs solar cell grown by dynamic hydride vapor phase epitaxy Open
We present an inverted metamorphic rear heterojunction ∼1.0 eV GaInAs solar cell deposited by dynamic hydride vapor phase epitaxy (D-HVPE) with high growth rate. This device uses a Ga1−xInxP compositionally graded buffer (CGB) to bridge th…
Control of Surface Morphology during the Growth of (110)-Oriented GaAs by Hydride Vapor Phase Epitaxy Open
We present a study of the effect of hydride vapor phase epitaxy (HVPE) growth conditions on the morphology of GaAs grown on vicinal and nominally exact (110) GaAs substrates. We evaluate epilayer surfaces using a combination of Nomarski mi…
Compositionally graded Ga1−xInxP buffers grown by static and dynamic hydride vapor phase epitaxy at rates up to 1 <i>μ</i>m/min Open
We demonstrate Ga1−xInxP compositionally graded buffers (CGBs) grown on GaAs with lattice constants between GaAs and InP by hydride vapor phase epitaxy (HVPE). Growth rates were up to ∼1 μm/min, and the threading dislocation density (TDD) …
View article: Effect of hydride vapor phase epitaxy growth conditions on the degree of atomic ordering in GaInP
Effect of hydride vapor phase epitaxy growth conditions on the degree of atomic ordering in GaInP Open
We report a systematic study of CuPt-type ordering in hydride vapor phase epitaxy (HVPE)-grown Ga0.5In0.5P. Selected-area electron diffraction reveals ordering in samples grown on (001) GaAs substrates offcut toward (11¯1)B. The ordering i…
Tunable Bandgap GaInAsP Solar Cells With 18.7% Photoconversion Efficiency Synthesized by Low-Cost and High-Growth Rate Hydride Vapor Phase Epitaxy Open
As market-dominant Si solar cell technology approaches its practical efficiency limit of 27.1%, a key challenge for the photovoltaic industry is to search for a low-cost ~1.7 eV top cell that can enable cost-competitive tandems with solar-…
View article: Characterization of Elastic Modulus Across the (Al<sub>1–<italic>x</italic></sub>Sc<sub><italic>x</italic></sub>)N System Using DFT and Substrate-Effect-Corrected Nanoindentation
Characterization of Elastic Modulus Across the (Al<sub>1–x</sub>Sc<sub>x</sub>)N System Using DFT and Substrate-Effect-Corrected Nanoindentation Open
Knowledge of accurate values of elastic modulus of (Al1-xScx)N is required for design of piezoelectric resonators and related devices. Thin films of (Al1-xScx)N across the entire composition space are deposited and characterized. Accuracy …
In situ Raman spectroscopy of pressure‐induced phase transformations in polycrystalline Tb <span>PO</span> <sub>4</sub> , Dy <span>PO</span> <sub>4</sub> , and Gd <sub> <i>x</i> </sub> Dy <sub> (1− <i>x</i> ) </sub> <span>PO</span> <sub>4</sub> Open
Xenotime Dy PO 4 and Gd x Dy (1− x ) PO 4 ( x = 0.4, 0.5, 0.6) (tetragonal I 4 1 amd zircon structure) have been studied at ambient temperature under high pressures inside a diamond anvil cell with in situ Raman spectroscopy. The typical R…
Ceramic materials in renewable energy: a module developed for hands-on learning Open
This document is a lesson plan for a short module describing the sintering of ceramic materials for STEM outreach. Colorado State science standards addressed by the module are included. The module is readily adapted for students in grades …
Development of GaInP Solar Cells Grown by Hydride Vapor Phase Epitaxy Open
We demonstrate the growth of homojunction GaInP solar cells by dynamic hydride vapor phase epitaxy for the first time. Simple unpassivated n-on-p structures grown in an inverted configuration with gold back reflectors were analyzed. Short …