Drift-Diffusion Modeling for Impurity Photovoltaic Devices

• Published in: IEEE transactions on electron devices Vol. 56; no. 12; pp. 3168 - 3174
• Main Authors: Lin, A.S., Phillips, J.D.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Computational efficiency; Computing time; Devices; Diffusion processes; Doping; Drift; Drift-diffusion model; Electronics; Energy; Exact sciences and technology; Impurities; intermediate levels (ILs); Mathematical models; Modeling; Natural energy; Optoelectronic devices; Photovoltaic cells; Photovoltaic conversion; Poisson equations; semiconductor; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor process modeling; solar cell; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Performance evaluation; Quantum dot; Impurity; intermediate levels (ILs); Conversion rate; Drift-diffusion model; semiconductor; Doping; Self consistency; Space charge; Doped materials; Poisson equation; Modeling; Photovoltaic cell; Solar cell; Transport process; Continuity equation; Optoelectronic device; Drift mobility
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2009.2032741

A 1-D drift-diffusion modeling for impurity photovoltaics is presented. The model is based on the self-consistent solution of Poisson's equation and carrier continuity equations incorporating generation and recombination mechanisms including the intermediate states. The model is applied to a prototypical solar cell device, where strong space charge effects and reduced conversion efficiency are identified for the case of lightly doped absorption regions. A doping compensation scheme is proposed to mitigate the space charge effects, with optimal doping corresponding to one-half the concentration of the intermediate states. The compensated doping device design provides calculated conversion efficiencies of approximately 40%, which is similar to the maximum expected values from prior 0-D models. The carrier transport between intermediate levels is shown to be noncritical for achieving the efficiency limit predicted by 0-D models. The qualitative behavior of the model is compared to existing experimental data on quantum dot solar cells.