Nanosecond pulsed-bias-actuated and exciton-dynamics-induced chirp in InGaN/GaN LEDs towards realizing electrically-tunable broadband light emitters

• Published in: Journal of luminescence 2021-01, Vol.229, p.117703, Article 117703
• Main Authors: Pendem, Vikas, Saha, Pratim Kumar, Chouksey, Shonal, Ganguly, Swaroop, Saha, Dipankar
• Format: Article
• Language: English
• Subjects: Boson; Exciton; GaN light emitting diode; Nanosecond pulsed-bias; Strained quantum wells; Transient quantum confined Stark effect
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2020.117703

Here, we show that a nanosecond electrical pulsed-bias actuation induces a chirp in the emission spectra of strained InGaN quantum well light emitting diodes (LEDs) that can be maneuvered to generate a broad tunable emission. The carrier and photon dynamics show that the emission wavelength can be tuned not only by the amplitude, but also by the on-time of the pulse. Whereas, the optical power can be tuned only by the on-time of the pulse. The time duration of the pulse is of the order of the carrier recombination time and the chirp is a consequence of the dominance of quantum confined Stark effect over junction temperature. Effect of polarization charges, applied bias, screening by injected carriers, carrier localization, and Bosonic exciton dynamics are amongst the imperative aspects that are considered for an accurate design of the pulsed-bias. •Pulsed-bias actuation introduces chirp in the emission spectra of InGaN LEDs.•The chirp is due to the turn-on dynamics determined by the transient QCSE.•The chirp can be maneuvered to design monolithic broadband LEDs.•On-time of the pulse also tunes the wavelength, in addition to the amplitude.