Temperature dependent admittance spectroscopy of GaAs/AlGaAs single-quantum-well laser diodes (SQWLDs)

In this study, the main electrical parameters, such as doping concentration (N_D), barrier height (Φ_CV), depletion layer width (W_D), series resistance (R_s) and Fermi energy level (E_F), of GaAs/Al_xGa_1−xAs single quantum well (SQW) laser diodes were investigated using the admittance spectroscopy (C-V and G/ω-V) method in the temperature range of 80-360 K. The reverse bias C⁻² vs. V plots gives a straight line in a wide voltage region, especially in weak inversion region. The values of Φ_CV at the absolute temperature (T = 0 K) and the temperature coefficient (α) of barrier height were found as 1.22 eV and −8.65 × 10⁻⁴ eV/K, respectively. This value of α is in a close agreement with α of GaAs band gap (−5.45 × 10⁻⁴ eV/K). Experimental results show that the capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of the diode are affected by not only temperature but also R_s. The capacitance-voltage-temperature (C-V-T) and conductance-voltage-temperature (G/ω-V-T) characteristics confirmed that temperature and R_s of the diode have effects on the electronic parameters in SQW laser diodes.