Effect of bottom cell properties on micromorph tandem device performance

Paola Delli Veneri, Lucia V. Mercaldo, Carlo Privato

Research output: Contribution to journalArticle

Abstract

Micromorph tandem solar cells represent an elegant way of overcoming the efficiency limits of single-junction solar cells and reducing the light-induced degradation of amorphous silicon films. Micromorph devices have been realised on Asahi U-type TCO-covered glass substrates by very high frequency plasma-enhanced chemical vapour deposition (VHF-PECVD) at 100 MHz at low substrate temperature (150°C). For the bottom cell, different growth regimes were explored by changing both chamber pressure and plasma power, with the aim of finding interesting regimes for industrial application. The effect of the structural composition of the microcrystalline absorber layer on the electrical parameters of the device was investigated. The highest efficiency (11.1%) is reached at 67 Pa and power to pressure ratio of 0.3 W/Pa. On the other hand, using a larger power to pressure ratio (0.5 W/Pa), high short circuit current density and constant efficiency over a wide silane concentration range were obtained. Homogeneity problems and low response at high wavelengths were found at large pressure (200 Pa). An evaluation of micromorph device stability was also carried out. © 2009 Taylor & Francis.
Original languageEnglish
Pages (from-to)2645 - 2654
Number of pages10
JournalPhilosophical Magazine
Volume89
Issue number28-30
DOIs
Publication statusPublished - Oct 2009

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All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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