Premium
Electronic Density of States of Amorphous CuGaS 2 and ZnGeAs 2
Author(s) -
Braun W.,
Cardona M.
Publication year - 1976
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220760126
Subject(s) - atomic physics , amorphous solid , valence (chemistry) , excitation , valence electron , electron , spectral line , inverse photoemission spectroscopy , photon energy , density of states , crystallite , atomic orbital , angle resolved photoemission spectroscopy , materials science , electronic structure , chemistry , molecular physics , photon , condensed matter physics , physics , crystallography , computational chemistry , optics , organic chemistry , quantum mechanics , astronomy
Measurements of the energy distribution curves of photoemitted electrons are made for amorphous ZnGeAs 2 , and CuGaS 2 . The energies of the exciting photons are 21.2 (HeI), 40.8 (HeII), 16.8 (NeI), and 26.9 eV (NeII). The amorphous thin films are prepared by sputtering from polycrystalline material onto aluminium substrates. The photoemission curves of the valence band of ZnGeAs 2 , show a two peak structure. The upper portions of the valence band (0 to 6 eV) are composed primarily of p‐orbitals of the As and Ge atoms. A doublet structure is observed and attributed to the different strength of the Zn‐As and Ge‐As bonds. The lower portion of the photoemission spectrum is dominated by a strong feature derived from the Zn 3d‐level. The photoemission spectra of CuGaS 2 , show a strong dependence upon excitation energy which is due to the varying admixture of 3d electrons of the Cu with the p‐valence electrons of Ga and S. The spectra are decomposed into approximate p and d densities of valence states by using experimental atomic cross sections for the corresponding partial excitation probabilities.