PL and PLE characterization of high current density resonant tunnelling diodes for THz applications

Low-temperature photoluminescence spectroscopy (PL) and excitation spectroscopy(PLE) are used to characterize and compare high current density resonant tunnelling diodes (RTD) structures. RTD structural characteristics are detected using X-Ray diffraction (XRD) while the electrical characteristics are detected by PL and PLE. Results are used to link the structure electrical properties to the RTD device IV characteristic. We started focusing the attention on the first quasi bound state (e l ) energy, fundamental for the RTD operation. PL is used to detect the TypeI and Type II QW radiative transitions. The e(1) state is obtained by the difference between the Type I (e(1)-hh(1)) and type II (conduction band-hhi) transitions. PLE is consequently used to detect the e2-hh2 transition from which we characterize the energy of the e2 state and its position with respect to the e1 state. Experimental data are confirmed by the RTDs device IV characteristics. We highlight the combination PL and PLE as a powerful, fast, and non-destructive characterization method to link wafer properties and device performance in RTD structures.