Blue-green light-emitting diode with patterned electrode: Spectral analysis

Abstract

Two step decomposition procedure was developed and implemented to analyze experimentally measured EL-spectra of light-emitting diode (LED) with mesh-like top electrode and two sets of InGaN/GaN quantum wells (QWs) for blue and green emissions. At a first step EL-spectra were decomposed into basic Gaussian functions (GFs) for blue, green, and violet emission lines. Then each of the basic GFs was decomposed into the secondary GFs which give reasonable ground to relate broadening of EL-spectrum to the position dependent compensation of quantum-confined Stark effect (QCSE) in the InGaN/GaN QWs. Metal strips prevent from extraction a portion of light not only with larger intensity but also with shorter wavelength comparing to those for the light extracted from the uncovered active region. Such a “cut-off” manifests itself in longer central peak wavelengths of the basic blue and green GFs obtained by EL-spectrum decomposition comparing to the emission spectra of blue and green QWs. Analysis of basic GFs allowed to evaluate quantitatively splitting of the injected charge carriers between blue and green QWs and the third source of violet emission. This can be useful in optimization-oriented modeling of the LED's performance.