Phone: þ82 62 715 2248, Fax: þ82 62 715 2204, Web: http://ssll.gist.ac.krWe report hybrid n-ZnO/i-InGaN/p-GaN solar cells in which the n-GaN layer of n-GaN/i-InGaN/p-GaN solar cell was replaced with n-type ZnO. In this study, inverted structures were used for hybrid ZnO/nitride solar cells where p-type GaN was first grown on sapphire substrate, followed by i-InGaN and n-ZnO layers. The as-fabricated device showed high series resistance and low energy conversion efficiency due to the formation of damaged p-GaN region during dry etching. On the other hand, formation of microrods on the p-GaN eased the removal of the damaged p-GaN resulting in significantly lowered series resistance and enhanced energy conversion efficiency.(a) n-ZnO/i-InGaN/p-GaN solar cell structure without microrods, (b) n-ZnO/i-InGaN/p-GaN solar cell structure with microrods, and (c) magnified image of the dashed box on (b).
Dyadic formulae for the medium parameters of the electromagnetic point-localized constitutive relations from the microscopic theory of optically-active molecules and crystals have been newly found, which clears out long-held controversy on reciprocity and equivalence.2006 Optical Society of America OCIS codes: 160.1190, 260.1180. It is quite extraordinary that, although the finding of optical activity in one of the optically-active crystals, α-quartz, was made almost two hundred years ago, 1 some significant controversy in its understanding around reciprocity characteristics still exists. 2, 3 The work in the chemistry community 4 focused on molecular structures and the calculation of rotatory power, while the work in the physics community focused on bianisotropic characteristics of the crystalline medium after accepting certain electromagnetic constitutive relations connecting the E, D, B, H fields. We believe that the afore-mentioned controversy has been largely due to the missing connection between the two viewpoints and to so-far nonexistent explicit microscopic expressions for the relevant medium tensors for the constitutive relations. In this study, we give such a theoretical connection between the two branches of study and attempt to develop a general theory by finding the explicit general expressions for the involved dyadic coefficients of the constitutive relations by showing the microscopic connection between the coefficient dyadics to the atomic dipoles, for the first time to our knowledge, thus demonstrating directly the reciprocity of the medium as a resulting macroscopic system. This ab-initio theory will then generalize the available classical model, 5, 6 mostly developed for dissymmetric optically active molecules in a liquid.In a molecule with dissymmetric bonds such as in most sugar molecules or in optically-active liquid crystals, external electric field polarizes the individual molecules to generate a nonvanishing macroscopic magnetization field 5, 6 M • (r, t) ≡ [n mol /2] N i = 1 [r i − r] × dπ i (t)/dt as well as the polarization field P(r, t) ≡ n mol N i = 1 π i (t) summing up all of N modes of electric dipole moments π i (t) ≡ π i π i (t), along the fixed π i direction, located at position r i within a single molecule, and finally taking the statistical expectation or even randomization over n mol molecules in unit volume. In the above formula, r is chosen near the center of a given molecule with "canonical magnetic dipoles" as the ones illustrated in Figs. 1(c)-(d). For a molecule with such a well-defined cylindrical symmetry, we suppose that N dipole resonance modes are well localized all in individual atoms. Then, there are N coupled-mode equations such asfor the jth dipole with charge q e , reduced mass m j , damping constant Γ j , resonance frequency Ω j , and the well-known coupling coefficients from dipole-dipole interaction, 5, 6 Fig. 1. The phase, direction, and magnitude of the oscillating dipoles attached to atoms in a molecule: Each of (a) and (b) gives a non-canonical magneti...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.