ErAs:InGaAlBiAs performance as a detector of THz pulses

We present our work on the elaboration of photoconductive switches (PCS) for the detection of THz pulses and the growth of the active material (ErAs:InGaAlBiAs) by a digital alloy approach using molecular beam epitaxy technique. In this semiconductor, the incorporation of Er above the solubility limit creates ErAs nanoparticles, decreasing the material's carrier lifetime. At the same time, ErAs nanoparticles have a strong pinning effect on the effective Fermi level position. Simultaneously, InGaAlBiAs offers enough degree of freedom to tune the bandgap and band alignment to the pinned Fermi level. These samples are characterized by different techniques to know the relevant properties. Dark resistance is obtained from Hall effect and Van der Pauw measurements, carrier lifetime from optical pump THz probe spectroscopy, optical band gap from spectrophotometry, material quality from high-resolution x-ray diffraction, and composition through Rutherford backscattering spectrometry. Finally, when the material meets the desired properties, we fabricated PCS to test its performance as a detector of THz pulses using 1550 nm wavelength excitation.