Analysis of fluctuation processes in forward-biased solar cells using noise spectroscopy

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2010-10, Vol.207 (10), p.2387-2394
• Main Authors: Macku, Robert, Koktavy, Pavel
• Format: Article
• Language: English
• Subjects: 1/f noise; Applied sciences; Energy; Exact sciences and technology; Natural energy; non-destructive diagnostic; Photovoltaic conversion; power spectral noise density; solar cells; Solar cells. Photoelectrochemical cells; Solar energy; transport mechanism
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201026206

The manufacturing technology of n+p solar cells currently features a very high level of perfection. Its further development appears to be limited by amongst other issues imperfect diagnostic methods. The objective of our research consists in non‐destructive studies of processes that influence specimen life and reliability. To this end, we are going to employ noise‐based analysis methods. These methods are closely related to some specimen bulk imperfections, crystal‐lattice‐defect‐induced traps, local‐stress‐subjected regions and, finally, breakdowns, which might bring about specimen destruction. Based on a detailed study and understanding of transport processes, regions in which noise is generated can be identified and appropriate technological measures can be proposed and adopted. Our research focuses, first of all, on the structures, which are inhomogeneous in their nature and are difficult to diagnose. On the basis of our experiments carried out to date, it has been established that the noise signal arises as a consequence of several concurrent processes. A noise model has been worked out and a mathematical description of separate noise source behaviour has been suggested. Our model includes the shot noise, the 1/f noise and a 1/f2 spectrum type noise and provides an account of the unconventional behaviour of solar cells.