| CPC H01L 31/03529 (2013.01) [H01L 31/186 (2013.01)] | 16 Claims |

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1. A solar cell, comprising:
a N-type substrate, wherein the N-type substrate has a first surface and the first surface is a textured surface having a plurality of pyramidal protrusions;
a P-type emitter formed on the first surface, wherein the P-type emitter comprises a first portion and a second portion, a top surface of the first portion comprises first pyramid structures formed on a first set of pyramidal protrusions of the plurality of pyramidal protrusions, one respective first pyramid structure of the first pyramid structures is an irregular tetrahedral structure, and at least a part of at least one inclined surface of the respective first pyramid structure is concave or convex relative to a center of the respective first pyramid structure, wherein a top surface of the second portion comprises second pyramid structures formed on a second set of pyramidal protrusions of the plurality of pyramidal protrusions, one respective second pyramid structure of the second pyramid structures is a regular tetrahedron structure, and inclined surfaces of the respective second pyramid structure are planar, and wherein in a direction perpendicular to the first surface of the N-type substrate, a junction depth of the first portion is greater than a junction depth of the second portion; and
a tunnel layer and a doped conductive layer sequentially formed over a second surface of the N-type substrate in a direction away from the N-type substrate;
wherein a crystal structure of the first portion of the P-type emitter has dislocations; and
wherein at least one first pyramid structure of the first pyramid structures comprises a substructure shaped as a sphere or a spheroid at a top of the at least one first pyramid structure.
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