An experimental diode spectrum at 300 K constant junction temperature is plotted in Fig. 3, together with the simulation based on Eq. (2). This plot shows that the exponential behavior described by Eq. (2) is not able to model the complete spectrum shape. However, the difference between the experimental curve and the curve according to Eq. (2) can be approximated by a Gaussian function. Therefore, a Gaussian function is added, resulting in the following analytical model :