Problem 15 - Chemistry: The 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 make an n-type semiconductor by doping GaAs, we can replace Ga with elements from Group 14 (carbon group) such as Si (Silicon) or Ge (Germanium) since they have 4 valence electrons, which is just one more than Ga's 3 valence electrons. Out of the Group 14 elements, Si and Ge are suitable choices due to their similar properties and common use in doping semiconductors.

Step 1: Identify the valence electron count of Ga

Ga or Gallium is in Group 13 of the periodic table, which means it has 3 valence electrons.

Step 2: Find elements with one more valence electron

We're looking for elements in the periodic table that have 4 valence electrons, as they have one more valence electron than Ga. They would be in Group 14, also known as the carbon group. Some elements in this group include C (Carbon), Si (Silicon), Ge (Germanium), Sn (Tin), and Pb (Lead).

Step 3: Determine a suitable candidate for doping

Considering the properties and availability of these elements, we can narrow down the options. C might not be a suitable choice due to its tendency to form insulating compounds. Si and Ge are commonly used for doping and have similar properties to Ga, making them good candidates.

Step 4: Result

In this case, suitable elements to replace Ga for making an n-type semiconductor are Si (Silicon) and Ge (Germanium).