Direct comparison of optical characteristics of InGaN-based laser diode structures grown on pendeo epitaxial GaN and sapphire substrates

Abstract

Direct comparison of optical properties and carrier dynamics of InGaN multiple quantum well (MQW) laser diode structures grown on pendeo epitaxial (PE)-GaN and sapphire substrates is reported. A strong increase in quantum efficiency and a dramatic reduction in stimulated emission threshold are observed for InGaN MQWs on PE-GaN substrates as compared to MQWs on sapphire substrates. Based on temperature-dependent time-resolved optical analysis, the authors find that a significant increase in nonradiative lifetime due to suppressed dislocation density plays an important role in enhancing optical properties of InGaN MQWs grown on PE-GaN substrates, resulting in radiative-process dominant emission even at room temperature.

Temperature-dependent photoluminescence in light-emitting diodes

“…The parameters C 1 and C 2 are two constants related to the density of non-radiative recombination centres in the samples. E A1 and E A2 are the activation energies corresponding to the non-radiative recombination process45464748. k B is Boltzmann's constant.…”

Deep traps in GaN-based structures as affecting the performance of GaN devices

“…[355]; improved performance of low-dislocation density LEDs was clearly illustrated in Ref. [368], for LDs see e.g. Ref.…”

Improving the internal quantum efficiency of QD/QW hybrid structures by increasing the GaN barrier thickness

“…The tting results are listed in Table 1, and the IQE is calculated by the I 300 K /I 10 K ratio, assuming that the NRRCs are frozen at 10 K. 40 All three E 2 values are larger than 60 meV, which are much larger than those in previous reports on InGaN/ GaN QWs, 33,34 quanticationally proving that the hybrid structures have stronger localization effects than the QWs. E 2 of A is larger than that of B and C, conrming the above qualitative assumption.…”

“…In addition, all PL intensities at different temperatures were measured under the same photon excitation and collection conditions (including laser power density, collection time, and slit width). The internal quantum efficiency (IQE) was calculated by the I 300 K /I 10 K ratio, assuming that the NRRCs are frozen at 10 K. 40 This is a widely used measurement method for IQE. Although the ratio I 300 K /I 10 K cannot give completely accurate internal quantum efficiency, it can give the correct variation trend of the internal quantum efficiency.…”