Wideband enhancement of infrared absorption in a direct band-gap semiconductor by using nonabsorptive pyramids

Abstract

Efficient trapping of the light in a photon absorber or a photodetector can improve its performance and reduce its cost. In this paper we investigate two designs for light-trapping in application to infrared absorption. Our numerical simulations demonstrate that nonabsorptive pyramids either located on top of an absorbing film or having embedded absorbing rods can efficiently enhance the absorption in the absorbing material. A spectrally averaged absorptance of 83% is achieved compared to an average absorptance of 28% for the optimized multilayer structure that has the same amount of absorbing material. This enhancement is explained by the coupled-mode theory. Similar designs can also be applied to solar cells.

Comparison of Ag and SiO2 Nanoparticles for Light Trapping Applications in Silicon Thin Film Solar Cells

“…Nanotechnology is a driving force in this research field. For instance, increased efficiency was demonstrated for organized arrays of dielectric nanoparticles (NPs) in the front and back side of thin film solar cells. − Also, metallic NPs have shown great promise as scattering structures in thin film solar cells to enhance light absorption within the localized surface plasmon resonance (SPR) region. − However, when integrated at the front end of the cell, the characteristic energy losses associated with metals limit the solar cell performance. , On the other hand, plasmonic structures placed at the back of a thin film solar cell have been demonstrated to enhance photocurrents. − …”

Enhancing silicon solar cell efficiency with double layer antireflection coating

“…They are generally examined by a computer system prior to using them on the solar cell surface to ensure that they enhance the solar energy transmitted to the cell, thus increasing its efficiency. Many studies have shown that the performance of single layer coating does not satisfy these requirements due to its narrow band at minimum reflectance [5]. Double layer ARCs (DLARCs) [5][6][7] have better performance when referring to broadband solar cells.…”

“…However, it is well known that many factors, electrical or optical, limit solar cell efficiency. Enhancing the efficiency of a given solar cell could be approached by using a good cell design and trying to have minimum reflectance on its surface by using ARC techniques [3][4][5]. ARCs have become one of the key issues in the mass production of silicon solar cells.…”

“…Many studies have shown that the performance of single layer coating does not satisfy these requirements due to its narrow band at minimum reflectance [5]. Double layer ARCs (DLARCs) [5][6][7] have better performance when referring to broadband solar cells. However, if one wants to achieve minimum reflectance of multiple wavelengths, additional layers must be added [8].…”

Compact photonic-crystal superabsorbers from strongly absorbing media

“…Traditional architectures may involve a top anti-reflection coating [3] to enhance the in-coupling of light and a back-reflector that facilitates a second light pass [2]. Many current works go beyond the latter approach with focused efforts around absorption optimization by nano/micro-structuring the absorber and/or its environment [14][15][16][17], including structures aiming for plasmon-mediated near-field enhancement in the vicinity of the absorber [4,5,8,9,11,18]. Photonic-crystals have been researched for absorption control both as back-reflector components [19][20][21] and directly as the absorptive medium [22][23][24][25][26].…”