In a particular semiconductor device, an oxide layer forms a barrier 0.6 nm wide and 9 eV high between two conducting wires. Electrons accelerated through a 4-V potential approach the barrier.

(a) What fraction of the incident electrons will tunnel through the barrier? Justify any approximations.

(b) Through what potential dierence should the electrons be accelerated in order to increase the tunneling fraction by a factor of 2?