Hi all, me again!(adsbygoogle = window.adsbygoogle || []).push({});

I'm trying to calculate the current created when an alpha particle strikes a silicon p-n detector, but I'm getting some strange numbers, so I was wondering if I was doing something fundamentally wrong...

My problems start when I try to calculate the reverse bias voltage required to create a depletion region equal to the range of alpha particles in Si, which I understand to be 7.29x10^{-5}m.

I use the following equation:

d= [itex](\frac{2 \epsilon V}{e N})^{\frac{1}{2}}[/itex]

where d is the depletion region (m) = 7.29x10^{-5}

Îµ is the ionisation energy of Si @ 300K (eV) = 3.62

e is the charge on an electron (C) = 1.602x10^{-19}

N is the charge carrier number density (m^{-3}) = 10^{19}

and V is the bias voltage.

rearranging I get

V = [itex]\frac{d^{2}eN}{2\epsilon}[/itex]

So far, so simple.

However, for some reason, after plugging the numbers in I get ~1.18x10^{-9}V for the bias voltage, which seems to be very small

So can anyone tell me what I'm doing wrong? Or is it right and my expectation of a voltage in the 10s of volts wrong?

Thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Help! Current generated by an alpha particle in silicon(reverse bias voltage problem)

Can you offer guidance or do you also need help?

**Physics Forums | Science Articles, Homework Help, Discussion**