Time-resolved pump-probe spectroscopic ellipsometry of cubic GaN, Part I: Determination of the dielectric function 

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2FCZ______%3A_____%2F23%3AN0000021" target="_blank" >RIV/CZ______:_____/23:N0000021 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.aip.org/aip/jap/article/134/7/075702/2907073/Time-resolved-pump-probe-spectroscopic" target="_blank" >https://pubs.aip.org/aip/jap/article/134/7/075702/2907073/Time-resolved-pump-probe-spectroscopic</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/5.0153091" target="_blank" >10.1063/5.0153091</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Time-resolved pump-probe spectroscopic ellipsometry of cubic GaN, Part I: Determination of the dielectric function 

Popis výsledku v původním jazyce

An ultra-fast change of the absorption onset for zincblende gallium-nitride (zb-GaN) ( fundamental bandgap: 3.23 eV) is observed by investigating the imaginary part of the dielectric function using time-dependent femtosecond pump-probe spectroscopic ellipsometry between 2.9 and 3.7 eV. The 266 nm (4.66 eV) pump pulses induce a large electron-hole pair concentration up to 4 similar to 10(20) cm(-3), which shift the transition energy between conduction and valence bands due to many-body effects up to approximate to 500 meV. Here, the absorption onset increases due to band filling while the bandgap renormalization at the same time decreases the bandgap. Additionally, the absorption of the pumpbeam creates a free-carrier profile within the 605 nm zb-GaN layer with high free-carrier concentrations at the surface, and low concentrations at the interface to the substrate. This leads to varying optical properties from the sample surface (high transition energy) to substrate (low transition energy), which are taken into account by grading analysis for an accurate description of the experimental data. For this, a model describing the time- and position-dependent free-carrier concentration is formulated by considering the relaxation, recombination, and diffusion of those carriers. We provide a quantitative analysis of optical experimental data (ellipsometric angles. and.) as well as a plot for the time-dependent change of the imaginary part of the dielectric function.

Název v anglickém jazyce

Time-resolved pump-probe spectroscopic ellipsometry of cubic GaN, Part I: Determination of the dielectric function 

Popis výsledku anglicky

An ultra-fast change of the absorption onset for zincblende gallium-nitride (zb-GaN) ( fundamental bandgap: 3.23 eV) is observed by investigating the imaginary part of the dielectric function using time-dependent femtosecond pump-probe spectroscopic ellipsometry between 2.9 and 3.7 eV. The 266 nm (4.66 eV) pump pulses induce a large electron-hole pair concentration up to 4 similar to 10(20) cm(-3), which shift the transition energy between conduction and valence bands due to many-body effects up to approximate to 500 meV. Here, the absorption onset increases due to band filling while the bandgap renormalization at the same time decreases the bandgap. Additionally, the absorption of the pumpbeam creates a free-carrier profile within the 605 nm zb-GaN layer with high free-carrier concentrations at the surface, and low concentrations at the interface to the substrate. This leads to varying optical properties from the sample surface (high transition energy) to substrate (low transition energy), which are taken into account by grading analysis for an accurate description of the experimental data. For this, a model describing the time- and position-dependent free-carrier concentration is formulated by considering the relaxation, recombination, and diffusion of those carriers. We provide a quantitative analysis of optical experimental data (ellipsometric angles. and.) as well as a plot for the time-dependent change of the imaginary part of the dielectric function.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Applied Physics

ISSN

0021-8979

e-ISSN

1089-7550

Svazek periodika

134

Číslo periodika v rámci svazku

7

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

10

Strana od-do

75702 (1-10)

Kód UT WoS článku

001050275100005

EID výsledku v databázi Scopus

2-s2.0-85168614404