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Center for Nonlinear Studies |
Improvement of efficiency of photovoltaic elements has been an important technological challenge for several decades. There are numerous mechanisms which lead to the charge relaxation in a bulk of a semiconductor. These mechanisms include spontaneous emission as well as phonon or impurity induced relaxation. While it is difficult to control these processes in a bulk of a semiconductor, their contribution can be significantly reduced with decreasing the size of the "working body" of the device. We propose a new paradigm for the design of high-efficiency photovoltaic nanodevices based on thin semiconductor films of controlled submicron thickness. Using a microscopic model of a thin dielectric layer we evaluate the efficiency of the thin film photocells and light emitting diodes