Time-resolved pump-probe spectroscopic ellipsometry of cubic GaN, Part II: Absorption edge shift with gain and temperature effects

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2FCZ______%3A_____%2F23%3AN0000022" target="_blank" >RIV/CZ______:_____/23:N0000022 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.aip.org/aip/jap/article/134/7/075703/2907074/Time-resolved-pump-probe-spectroscopic" target="_blank" >https://pubs.aip.org/aip/jap/article/134/7/075703/2907074/Time-resolved-pump-probe-spectroscopic</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/5.0153092" target="_blank" >10.1063/5.0153092</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Time-resolved pump-probe spectroscopic ellipsometry of cubic GaN, Part II: Absorption edge shift with gain and temperature effects

Popis výsledku v původním jazyce

We recently published a study concerning femtosecond pump-probe absorption edge spectroscopy of cubic GaN (fundamental bandgap: 3.23 eV), resulting in the transient dielectric function. In the present study, we continue our investigations of those pump-probe measurements by determining the time-dependent transition energy at the Fermi-vector between the conduction and valence bands. The generation of electron-hole pairs by the 266 nm pump-beam (4.66 eV) shifts the absorption edge by approximate to 500 meV within 1 ps due to many-body effects like band-filling and bandgap renormalization. Modeling this ultra-fast change is achieved by converting the transition energies into free-carrier concentrations, assuming the electron contributions to be dominant. We consider the relaxation, recombination, and diffusion of those free-carriers as well as either an additional gain-recombination or temperature effects. This allows for describing the transition energies on short time scales. Both models yield similar values for the characteristic relaxation time (similar to 0.21 ps), recombination time (similar to 25 ps), and diffusion coefficient (similar to 1 cm(2)/s).

Název v anglickém jazyce

Time-resolved pump-probe spectroscopic ellipsometry of cubic GaN, Part II: Absorption edge shift with gain and temperature effects

Popis výsledku anglicky

We recently published a study concerning femtosecond pump-probe absorption edge spectroscopy of cubic GaN (fundamental bandgap: 3.23 eV), resulting in the transient dielectric function. In the present study, we continue our investigations of those pump-probe measurements by determining the time-dependent transition energy at the Fermi-vector between the conduction and valence bands. The generation of electron-hole pairs by the 266 nm pump-beam (4.66 eV) shifts the absorption edge by approximate to 500 meV within 1 ps due to many-body effects like band-filling and bandgap renormalization. Modeling this ultra-fast change is achieved by converting the transition energies into free-carrier concentrations, assuming the electron contributions to be dominant. We consider the relaxation, recombination, and diffusion of those free-carriers as well as either an additional gain-recombination or temperature effects. This allows for describing the transition energies on short time scales. Both models yield similar values for the characteristic relaxation time (similar to 0.21 ps), recombination time (similar to 25 ps), and diffusion coefficient (similar to 1 cm(2)/s).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

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

7

Strana od-do

75703 (1-7)

Kód UT WoS článku

001050275100003

EID výsledku v databázi Scopus

2-s2.0-85168591747