Istituto dei materiali per l'elettronica ed il magnetismo     
Rossi F., Salviati G., Pavesi M., Manfredi M., Meneghini M., Zanoni E., Zehnder U. Field dependence of the carrier injection mechanisms in InGaN Quantum wells: Its effect on the luminescence properties of blue light emitting diodes. In: Journal of Applied Physics, vol. 103 article n. 093504. American Institute of Physics, 2008.
Carrier injection and radiative recombination processes in InGaN/GaN blue light emitting diodes are investigated by bias-dependent cathodoluminescence. The samples are designed with a single-quantum-well (SQW) light emitter and an adjacent multi-quantum-well (MQW) carrier injector of lower In content. In unbiased samples, the MQW emission dominates over the SQW at high temperatures (T>160 K) or low beam currents (IB<5 nA). This is ascribed to changes in the device energy band diagram, dependent on the field in the p-n junction and on the level of electron beam induced excitation of excess carriers. A field screening, resulting in a forward biasing of the devices, is highlighted. A maximum value of +2.65 V is reached at T=100 K for a carrier generation rate G0=5.4x1013 s−1. At a fixed electron beam power, the effects of an external applied field on the emitter efficiency are considered. The SQW emission is promoted in the forward-current regime, while in the reverse-current regime (−1
vedi abstract inglese
URL: http://scitation.aip.org/japo/
DOI: 10.1063/1.2903514
Subject light emitting diodes, cathodoluminescence

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