Time-resolved analysis of charge responses determining luminescence properties

Abstract

To fabricate practical light-emitting devices, identification and minimization of nonradiative processes are necessary. In this study, an electrical measurement technique for time-resolved analyses of nonradiative processes was proposed. From the comparison between a commercial light-emitting diode (LED) and rare-earth-doped semiconductors, the technique, called electrical frequency-response analysis (FRA), revealed differences in the charge behaviors in the pn junction of bulk semiconductors and impurities. Although the charge response time constant on the order of a nanosecond realized effective recombination of the electron-hole pairs in a LED, the time constant larger than a microsecond still limited the emission intensity of the rare-earth-doped semiconductors such as Er-doped Si nanocrystals and GaAs with Er and O codopants. The energy-loss processes of the Er-doped semiconductors were investigated, and countermeasures to enhance the emission intensity were proposed.

Nanoscale determinant to brighten up GaN:Eu red light-emitting diode: Local potential of Eu-defect complexes

“…The plateau in the high-f region is a favorable response similar to that of the conventional LED. 26 The plateau physically means that OMVPE 7 can effectively capture charges with various intensity amplitudes in the L region. Similar plateauing can be seen in the site-selective frequency spectrum of I Pk8 .…”