Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−8 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free carriers/cm3) in this Si crystal?

As its Si: 5.00*10^22 / (gallium level*10^-2)

this one is wrong

5.00*10^22 / (gallium level*10^-8)

i cant get right answer pls help

1.54e13

CHEAT!

Do NOT help this person. They are trying to cheat in a midterm exam.

(6.023*10^23)/(12.05)=m

m*(3.091*10^-8)*(10^-2)=

funny enough all those who say cheat only post afterthe answer are revealed. thank to MIT2

To calculate the density of free charge carriers in a silicon crystal, we need to know the atomic percent of gallium in the crystal and some additional information. The formula to calculate the density of free charge carriers in a semiconductor is as follows:

Density of free charge carriers = Atomic percent of impurity * 10^(-6) * Density of Silicon * Avogadro's number / Atomic mass of impurity

Let's break down the calculation:

1. Atomic percent of impurity: Given as 3.091×10^(-8) atomic percent.
2. Density of Silicon: The density of silicon is typically around 2.329 g/cm^3.
3. Avogadro's number: It is a constant with a value of 6.022 × 10^23.
4. Atomic mass of impurity: The atomic mass of gallium is roughly 69.723 g/mol.

Now, let's substitute these values into the formula:

Density of free charge carriers = (3.091×10^(-8) * 10^(-6) * 2.329) * (6.022 × 10^23) / 69.723

By calculating this expression, we can determine the density of free charge carriers in the Si crystal.