Density of states in hydrogenated amorphous germanium seen via optical absorption spectra

✍ Scribed by Y. Bouizem; A. Belfedal; J.D. Sib; L. Chahed

• Book ID: 104166129
• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 150 KB
• Volume: 126
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/s0038-1098(03)00271-0

✦ Synopsis

We propose and discuss a deconvolution procedure to analyze quantitatively optical absorption spectra. This procedure is used to determine the density of states distribution in the mobility gap of a-Ge:H films studied by a combination of standard optical transmission measurements, photothermal deflection spectroscopy and constant photocurrent method. This yields a Gaussian distribution for the gap states centered at E D ¼ ð0:60 ^0:01Þ eV below the conduction band edge, with a width at half height equal to (0.32 ^0.01) eV. A good linear correlation is also observed between the deep-defect density N D and the corresponding absorption coefficient at a photon energy of 0.7 eV.