**1. Introduction**

Solar cells depend upon the photovoltaic effect for their operation that converts the incident energy of sunlight directly into electricity using the electronic properties of semiconducting materials. In the past few decades, silicon wafers have been used to fabricate the overwhelming majority of solar cells in the very dynamic photovoltaic industry because of the abundance and non‐toxicity of silicon, the simplicity of cell fabrication process, and the vast amount of processing knowledge developed and accumulated in the microelectronics industry. Simply speaking, silicon wafer‐based solar cells generate electricity via absorbing photons and

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

generating electron‐hole pairs that are separated by a *pn*‐junction and then flow to electrical contacts on the front and back sides to perform work in external circuit, as shown in the **Figure 1**.In addition, due to several advantages of *n*‐type (typically phosphorus‐doped) silicon wafers over *p*‐type (typically boron‐doped), including better tolerance to common impurities (e.g. iron) [1], higher bulk lifetime and no light‐induced degradation (LID) [2], *n*‐type silicon solar cells with high efficiency can be potentially more cost‐effective than *p*‐type silicon solar cells. Hence, the focus in this chapter will be on high‐efficiency front junction *n*‐type crystalline silicon solar cell with both sides passivated and contacted, including their operating principle, advanced cell structures, surface passivation and fabrication schemes.

**Figure 1.** Schematic energy band diagram of a front junction *n*‐type silicon solar cell in a non‐equilibrium (with illumi‐ nation), including photon absorption, carrier generation and separation.
