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Perovskites fabricated on textured silicon surfaces for tandem solar cells
摘要： The silicon surface texture significantly affects the current density and efficiency of perovskite/silicon tandem solar cells. However, only a few studies have explored fabricating perovskite on textured silicon and the effect of texture on perovskite films because of the limitations of solution processes. Here we produce conformal perovskite on textured silicon with a dry two-step conversion process that incorporates lead oxide sputtering and direct contact with methyl ammonium iodide. To separately analyze the influence of each texture structure on perovskite films, patterned texture, high-resolution photoluminescence (μ-PL), and light beam-induced current (μ-LBIC), 3D mapping is used. This work elucidates conformal perovskite on textured surfaces and shows the effects of textured silicon on the perovskite layers with high-resolution 3D mapping. This approach can potentially be applied to any type of layer on any type of substrate.
关键词： tandem solar cells,dry two-step conversion process,perovskite,textured surfaces,silicon
更新于2025-09-23 15:21:01
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Geometric influence of cylindrical surface curvature on the electrostatics of thin film transistors
摘要： Thin film transistor (TFTs) based integrated circuits on flexible substrates promise interesting approaches to human interface systems. TFTs have been fabricated on textured surfaces such as textiles, paper, artificially corrugated substrates and fibers. This can result in the metal-insulator-semiconductor (MIS) stack being significantly distorted from a planar geometry to having high curvature. Although the direct deposition on textured surfaces does not result in mechanical stress (as opposed to that seen during bending, buckling, wrinkling), the geometry of high curvature can influence the characteristics of the TFT. Here we present a closed form analytical model describing the impact of high curvature on the electrical performance of the TFT. Models are obtained from the solution to the Poisson-Boltzmann equation in polar co-ordinates and are limited to cylindrical surface (zero Gaussian curvature) with the ratio of radius of curvature of the semiconductor-insulator interface, rsi, to insulator thickness, ti, ranging from rsi/ti = 2 to rsi/ti = 50. Models are verified using Technology Computer-Aided Design (TCAD) simulations performed using amorphous galium indium zinc oxide (a-GIZO). Studies show that when the semiconductor-insulator interface is curved convex (normal vector into the gate) the interfacial free carrier concentration increases by 50% (for rsi/ti = 2) to 8.5% (for rsi/ti = 15) as compared to planar TFTs. On the other hand, when the curvature is concave, the free carrier concentration decreases by those percentages as compared to planar TFTs. Thus curvature can modulate TFT transconductance. Models show that the impact of curvature becomes negligible (< 4% variation) for rsi/ti > 25. Techniques to generalize the results to periodic cylindrical surfaces and other semiconducting materials are discussed along with experimental verification. This work forms an analytical basis to understand the behavior of TFTs fabricated on textured substrates.
关键词： textured surfaces,TCAD simulations,a-GIZO,flexible substrates,Thin film transistor,Poisson-Boltzmann equation
更新于2025-09-09 09:28:46