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<p>and <a href="page.php?w=electron_hole">electron hole</a>s, collectively known as <a href="page.php?w=charge_carrier">charge carrier</a>s. Doping a semiconductor with a small proportion of an atomic impurity, such as <a href="page.php?w=phosphorus">phosphorus</a> or <a href="page.php?w=boron">boron</a>, greatly increases the number of free electrons or holes within the semiconductor. When a doped semiconductor contains excess holes, it is called a <a href="page.php?w=p-type_semiconductor">p-type semiconductor</a> (p for positive <a href="page.php?w=electric_charge">electric charge</a>);</p><p>
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