2026-09-26T06:02:49Z https://epublications.vu.lt/oai

oai:vu.lt:elaba:210578936 2026-07-04T21:23:51Z openaireNDLTDDRIVER

Ultravioletinės srities šviesos diodų žemadažnio triukšmo tyrimas /Low-frequency noise investigation of ultraviolet light-emitting diodes.Pliaterytė, Ingrida,info:eu-repo/semantics/openAccessThe 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.Institutional Repository of Vilnius Universityinfo:eu-repo/semantics/bachelorThesislit2024application/pdfhttps://epublications.vu.lt/object/elaba:210578936/210578936.pdfhttps://repository.vu.lt/VU:ELABAETD210578936&prefLang=en_US