Photonic molecules and spectral engineering

This chapter reviews the fundamental optical properties and applications of pho-tonic molecules (PMs) - photonic structures formed by electromagnetic coupling of two or more optical microcavities (photonic atoms). Controllable interaction between light and matter in photonic atoms can be further modified and en-hanced by the manipulation of their mutual coupling. Mechanical and optical tunability of PMs not only adds new functionalities to microcavity-based optical components but also paves the way for their use as testbeds for the exploration of novel physical regimes in atomic physics and quantum optics. Theoretical studies carried on for over a decade yielded novel PM designs that make possible lowering thresholds of semiconductor microlasers, producing directional light emission, achieving optically-induced transparency, and enhancing sensitivity of microcavity-based bio-, stress- and rotation-sensors. Recent advances in material science and nano-fabrication techniques make possible the realization of optimally-tuned PMs for cavity quantum electrodynamic experiments, classical and quantum information processing, and sensing.Comment: A review book chapter: 29 pages, 19 figure

Investigation of methods for adhesion characterization of evaporated aluminum layers

This paper analyzes methods for measuring the adhesion quality of aluminum (Al) rear metallization deposited by means of physical vapour deposition (PVD) on rear passivation layers of passivated emitter and rear silicon solar cells (PERC). Since the standard test procedures for adhesion testing of solar cells cannot be applied, a peel-test and a direct-pull method are introduced and used for measuring the adhesion of test samples; criteria for adhesion evaluation are developed and applied. The results of adhesion tests are compared and are in good general agreement. The applicability of the two methods is discussed and it is found that the peel-test shows more reliable results whereas the direct-pull method is easier in preparation. Moreover, the results of the test samples show sufficiently good adhesion quality for the PVD rear metallization of PERC solar cells

Competitiveness of a European PV Manufacturing Chain

Today, solar power is one of the cheapest ways of providing energy internationally, partly because of the excellent R&D work in Europe. Prices of modules have fallen by half in the past three years, and at the same time the use of solar power has been steadily increasing. The reason why there has been an increase in the use of solar energy in Europe and Germany is the achievement of the climate targets of the Paris Agreement. While the machines for the production of solar modules are still manufactured in Germany, the production of cells has now almost completely migrated to Asia. Therefore, the VDMA commissioned a study from Fraunhofer ISE to evaluate whether the production of solar modules at competitive costs could again be realized in Europe. This paper presents the results of the VDMA study