- Why does band diagram shift in diode?
Why does the band diagram shift up or down when I apply potential? Why does it shift down when positive potential is applied? Professor said it's because electron has negative charge and so we consider downward direction as positive because we have -qE as some energy for electron to enter free space.
But I didn't understand it. If I apply n-region with positive potential, then am I increasing or decreasing electron concentration in Surface. From Energy band diagram I am increasing Electron concentration as the Ef is toward Ec now. But I dont understand how?