Problem 15 - Chemistry Central Science

Question

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

Step-by-Step Solution

Answer

To dope GaAs and make an n-type semiconductor, suitable elements to replace gallium (Ga) should belong to group 14, with 4 valence electrons. The most common and effective dopant elements for this purpose are silicon (Si) and germanium (Ge).

Step 1: Determine the number of valence electrons for gallium (Ga)

Identify the group to which gallium belongs in the periodic table. Gallium belongs to group 13, which means it has 3 valence electrons.

Step 2: Find the dopant with an extra valence electron

To make an n-type semiconductor, the dopant needs to have one more valence electron than the replaced element (gallium in this case). Therefore, the dopant element should belong to group 14, which means it has 4 valence electrons.

Step 3: Select the suitable dopant element(s)

Elements belonging to group 14 that can potentially replace gallium are carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). However, considering the practicality and efficiency of doping, silicon (Si) and germanium (Ge) are the most common and effective dopant elements for turning GaAs into an n-type semiconductor. In conclusion, silicon (Si) and germanium (Ge) are the best choices to dope GaAs to make an n-type semiconductor with an element to replace gallium (Ga).