Ultravioletinės srities šviesos diodų žemadažnio triukšmo tyrimas /

The aim of this work was to investigate low-frequency noise characteristics of UV LEDs, evaluate simultaneous cross-correlation coefficient between electrical and optical fluctuations and apply correlation method for InGaN-based LEDs. Two AlGaN-based LEDs (275 nm) and two InGaN-based LEDs (370 and 385 nm) were investigated. All investigated LEDs exhibited 1/f^α electrical and optical fluctuations while electrical generation-recombination noise with Lorentzian-type spectra were additionally observed in some current ranges of AlGaN-based LEDs. Shot noise was also observed in all optical spectra at higher frequencies. 1/f^α noise components of InGaN-based LEDs optical noise showed to be significantly more intense however the level of normalised optical noise was higher in AlGaN LEDs. Simultaneous cross-correlation coefficient (10 Hz – 20 kHz) measured close to zero in all current range for the first AlGaN-based LED and slightly negative for the second. InGaN-based LEDs exhibited higher correlation coefficients with peak values of ~63% and ~47% for each LED. Correlation method was used for InGaN-based diodes to investigate cross-correlation coefficients at its peak values which yielded that almost all observed low-frequency fluctuations of the first InGaN-based LED and approximately half of 1/f and 70% of 1/f^α fluctuations of the second InGaN-based LED are related with defects in active layer.

Grantor dc:publisher

Institutional Repository of Vilnius University

Year dc:date

2024

Author dc:creator

• Pliaterytė, Ingrida,

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

lit

Repository record dc:identifier

https://repository.vu.lt/VU:ELABAETD210578936&prefLang=en_US

OAI identifier oai:identifier

oai:vu.lt:elaba:210578936