Which of the following semiconductor materials contains excess free electrons?

In semiconductor manufacturing, base materials like silicon are doped with specific impurities to change their electrical properties. When a semiconductor is doped with an element that has more valence electrons than the base material, it results in an abundance of free electrons. Because electrons carry a negative charge, this resulting material is called 'N-type' semiconductor material. The 'N' stands for Negative, directly pointing to these excess free electrons. Conversely, 'P-type' material is doped to create an excess of 'holes' (a lack of electrons), which act as positive charge carriers. Understanding this N-type (negative/electrons) and P-type (positive/holes) relationship is fundamental to understanding how diodes and transistors operate.