Heidi
Member
I was trying to figure out how to graphically represent the relationship between the charge stored in immobile ions in the depletion region of a pn junction and the reverse bias voltage across the junction.
What I know is that when the reverse bias voltage is greater, more bound charge is stored in the depletion region of a pn junction, with positive ions in the n side and equal amount of negative ions in the p side. What I can't understand is that when the relation between the stored charge and the bias voltage is represented graphically as in Figure 3.62(a) in the attached files 1 and 2, why the depletion layer charge, Qdep, is plotted as negative when reverse biased? And when forward biased, the depletion layer charge should be reduced, but why is Qdep positive and increasing with vD?
Do you think the depletion charge Qdep is referring to the positive bound charge or the negative one? Would you please show me how I can understand Figure 3.62(a)?
What I know is that when the reverse bias voltage is greater, more bound charge is stored in the depletion region of a pn junction, with positive ions in the n side and equal amount of negative ions in the p side. What I can't understand is that when the relation between the stored charge and the bias voltage is represented graphically as in Figure 3.62(a) in the attached files 1 and 2, why the depletion layer charge, Qdep, is plotted as negative when reverse biased? And when forward biased, the depletion layer charge should be reduced, but why is Qdep positive and increasing with vD?
Do you think the depletion charge Qdep is referring to the positive bound charge or the negative one? Would you please show me how I can understand Figure 3.62(a)?
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