| Ideality factor is an important parameter that can be extracted from current-voltage (I-V) characteristics of a diode. We analyze ideality factors for bulk, quantum well and quantum dot diodes with respect to recombination mechanisms by building a theoretical model based on the relationship between carrier densities, current and voltage for a p-i-n heterostrucutre. We find that irrespective of the nature of confinement of carriers, ideality factor due to defect, radiative and Auger recombinations are 2, 1 and 0.667 respectively. We examine the role of differential change in carrier densities with respect to applied voltage in order to find a relationship between ideality factors in non-degenerate and degenerate regions. The effect of series resistance at higher currents is analyzed. We observe that the conventional method of extracting the ideality factor and series resistance for a quantum dot diode can sometimes yield erroneous results if degeneracy is not taken into account. |
