Open AccessCritical dependence of the excitonic absorption in cuprous oxide on experimental parameters
Author(s) -
Julian Heckötter,
M. Freitag,
M. Abmann,
D. Fröhlich,
Manfred Bayer,
P. Grunwald,
Stefan Scheel
Publication year - 2018
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2018.08.46251.19gr
Subject(s) - exciton , rydberg formula , band gap , excited state , oscillator strength , absorption (acoustics) , materials science , excitation , oxide , condensed matter physics , absorption band , atomic physics , molecular physics , chemistry , physics , optoelectronics , spectral line , optics , quantum mechanics , ion , metallurgy , composite material , ionization , organic chemistry
We study the modification of the exciton absorption in cuprous oxide by the presence of free carriers excited through above band gap excitation. Without this pumping, the absorption spectrum below the band gap consists of the yellow exciton series with principal quantum numbers up to more than n = 20, depending on the temperature, changing over to an about constant, only slowly varying absorption above the gap. Careful injection of free carriers, starting from densities well below 1 μm^–3, leads to a reduction of the band gap through correlation effects. The excitons in the Rydberg regime above n = 10 remain unaffected until the band gap approaches them. Then they lose oscillator strength and ultimately vanish upon crossing with the band gap.