Experimental study on the mechanism governing spectral shifts in low power 670 nm AlGaInP multiple quantum well (MQW) laser diodes over temperature range 5–45 °C

Abstract

We report on the temperature-dependent spectral shifts in low power 670 nm AlGaInP multiple quantum well red laser diodes due to band gap narrowing at room temperatures (5–45 °C). The spectral shift mechanism is explored with a threshold current density of 11.41 kA/cm2 and a good characteristic temperature of 114 K. The photoluminescence peak intensity shifts towards higher wavelengths and the full width at half maximum increases with increase in temperature from 5 to 45 °C. We use a Hamiltonian system considering the effective mass approximation to formulate the carrier concentrations. The band gap narrowing value determined by a simple formula amounts to 59.15 meV and displays N1/3 dependence at higher densities. The carrier density dependence conveys that the redshift of the spectral emission is due to band gap narrowing.