This paper aims to present a proposed npn solar cell microstructure based on low cost heavily
doped Silicon wafers. The physical perception of the proposed structure is based on the idea of
vertical generation and lateral collection of light generated carriers. It should be mentioned that
our structure can be utilized whenever the diffusion length of photogenerated electron hole pairs
is smaller than the penetration depth of the solar radiation. The enhancement in the structure
performance is attained by the optimization of the structure technological and geometrical
parameters and based on practical considerations. This enhancement enables achieving the
maximum possible structure conversion efficiency. Moreover, the optical performance, in terms
of the spectral response and external quantum efficiency, is presented. The optimization is
carried out using SILVACO TCAD process and device simulators. The main parameters used in
optimization include the thickness and doping of the top n+ layer as well as the sidewall emitter.
Additionally, the structure base width along with the notch depth are considered. Finally, back
surface treatment is introduced. The structure conversion efficiency in the initial step before
optimization was 10.7%. As a result of the optimization process, the structure conversion
efficiency is improved to about 15% above the initial case study by 4%. |
