Photoreflectance study of the surface state density and distribution function of InAlAs

Citation
Js. Hwang et al., Photoreflectance study of the surface state density and distribution function of InAlAs, J APPL PHYS, 89(1), 2001, pp. 396-400
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF APPLIED PHYSICS
ISSN journal
0021-8979 → ACNP
Volume
89
Issue
1
Year of publication
2001
Pages
396 - 400
Database
ISI
SICI code
0021-8979(20010101)89:1<396:PSOTSS>2.0.ZU;2-S
Abstract
Photoreflectance is used to investigate the band gap, built-in electric fie ld, and surface Fermi level of a series of lattice-matched In0.52Al0.48As s urface-intrinsic n(+) structures having different undoped layer thicknesses . Experimental results indicate that, although the built-in electric field depends on the undoped layer thickness, there is a range of thickness withi n which the surface Fermi level is weakly pinned. From the dependence of el ectric field and surface Fermi level on the undoped layer thickness, we can determine that the surface states distribute over two separate regions wit hin the energy band gap. The densities of the surface states are evaluated as well. Moreover, the dependence of the built-in electric field on undoped layer thickness is converted into the dependence of surface state density on the surface Fermi level in order to theoretically and exactly calculate the energy spectrum of the surface state density using a Guassian distribut ion function. The center and width of the distribution near the conduction band are obtained from the fitting parameters. (C) 2001 American Institute of Physics.