Accuracy of activation energy from Arrhenius plots and temperature-dependent internal photoemission spectroscopy

In this work, the activation energy obtained from the temperature dependent internal photoemission spectroscopy (TDIPS) and thermionic dark currents using GaAs/AlGaAs photodetectors are compared. Different barrier heights within the p-type GaAs/AlGaAs heterostructures are studied. The temperature dependent spectral response shows the red-shifting of the detector threshold wavelength for increasing temperature due to the decreasing band-offset. The activation energy extracted from Arrhenius plot of the dark current-voltage-temperature (I-V-T), and measured spectral response show the carrier activation energy increases with increasing Al mole fraction and decreases with increasing doping density. For Infrared detectors with ≤6.5 μm, the Arrhenius analysis yields the values of activation energy with less than 5% deviation from the actual or TDIPS fitting values. However, for detectors with longer threshold wavelengths (≫9.3 μm), activation energy extracted from the Arrhenius plot leads to energy values which deviate more than ~10% from the corresponding TDIPS values. The higher percentage deviation (≫10%) of activation energy determined by Arrhenius plot from the corresponding TDIPS values attribute to the temperature dependent Fermi distribution tailing effect and Fowler–Nordheim tunneling current.