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

Abstract

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 x Ga 1− x As 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.