Problem 16 - Chemistry: The Central Science

Question

If you want to dope GaAs to make a p-type semiconductor with an element to replace As, which element(s) would you pick?

Step-by-Step Solution

Answer

To dope GaAs (Gallium Arsenide) and make a p-type semiconductor, you should choose Antimony (Sb) as the dopant element. This is because Sb has one more valence electron than As (Arsenic), which will create acceptor sites and increase the conductivity of the material, leading to a p-type semiconductor.

Step 1: Identify the group and valence electrons of As

The first step is to find As in the periodic table and determine its group and valence electrons. As has 5 valence electrons and belongs to Group 15 (also known as Group VA or Nitrogen Group).

Step 2: Find the elements with one more valence electron than As

Since we need to dope GaAs with an element that has one more valence electron than As, we should look for elements in the same group with one more valence electron. In Group 15, the element with one more valence electron than As is Antimony (Sb), which has 5 valence electrons and is positioned directly below As in the periodic table.

Step 3: Determine if the chosen element is suitable for doping GaAs

Antimony (Sb) is the most suitable candidate for replacing As to make a p-type semiconductor since it has one more valence electron than As. Doping GaAs with Sb will introduce acceptor sites where the extra electrons can move freely, increasing the conductivity and creating a p-type semiconductor. In conclusion, to dope GaAs and make a p-type semiconductor by replacing As atoms, you should choose Antimony (Sb) as the dopant element.