Combined electrical and resonant optical excitation characterization of multi-quantum well InGaN-based light-emitting diodes

Journal Article · Fri Jul 15 00:00:00 EDT 2016 · AIP Advances

DOI:https://doi.org/10.1063/1.4959100· OSTI ID:22611459

Maaskant, P. P.; Corbett, B. ^[1]; Kappers, M. J.; Humphreys, C. J. ^[2]

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1. Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork (Ireland)
2. Dep. Material Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge (United Kingdom)

We present a comprehensive study of the emission spectra and electrical characteristics of InGaN/GaN multi-quantum well light-emitting diode (LED) structures under resonant optical pumping and varying electrical bias. A 5 quantum well LED with a thin well (1.5 nm) and a relatively thick barrier (6.6 nm) shows strong bias-dependent properties in the emission spectra, poor photovoltaic carrier escape under forward bias and an increase in effective resistance when compared with a 10 quantum well LED with a thin (4 nm) barrier. These properties are due to a strong piezoelectric field in the well and associated reduced field in the thicker barrier. We compare the voltage ideality factors for the LEDs under electrical injection, light emission with current, photovoltaic mode (PV) and photoluminescence (PL) emission. The PV and PL methods provide similar values for the ideality which are lower than for the resistance-limited electrical method. Under optical pumping the presence of an n-type InGaN underlayer in a commercial LED sample is shown to act as a second photovoltaic source reducing the photovoltage and the extracted ideality factor to less than 1. The use of photovoltaic measurements together with bias-dependent spectrally resolved luminescence is a powerful method to provide valuable insights into the dynamics of GaN LEDs.

• OSTI ID: 22611459
• Journal Information: AIP Advances, Vol. 6, Issue 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARRIERS
COMPARATIVE EVALUATIONS
DIFFUSION BARRIERS
EMISSION SPECTRA
EXCITATION
GALLIUM NITRIDES
INDIUM COMPOUNDS
INJECTION
LIGHT EMITTING DIODES
OPTICAL PUMPING
PHOTOLUMINESCENCE
PHOTOVOLTAIC EFFECT
PIEZOELECTRICITY
QUANTUM WELLS
VISIBLE RADIATION