Infrared reflection and transmission of undoped and Si-doped InAs grown on GaAs by molecular beam epitaxy

Abstract

Nodestructive optical methods, based on measurements of the 'plasma edge' and the Moss-Burstein shift, are investigated as contactless reflection and transmission spectra of undoped and Sidoped lnAs grown on GaAs by MBE are studied. A curve-fitting procedure is developed to fit the reflectivity spectra with or without phonon-plasmon coupling. The range of carrier concentrations over which these optical methods can provide useful characterization is evaluated. The effective mass determined from 'plasma edge' measurements agrees well with the simple Kane model for n below 2.7 x 10'' c t r 3 . For n above 4 x I O ' ' cm-3, the sample effective mass deviates considerably from the simple Kane model. Excitonic structure in the absorption edge is reported for high-purity undoped samples.

Infrared studies of hole-plasmon excitations in heavily-doped p-type MBE-grown GaAs:C

“…The first term in Eq. ͑2͒ is equivalent to the reflectivity of a thin absorbing film on an opaque substrate, 22,27,28,32 and the second term is derived from the sum of a geometric series of multiple reflections across the substrate. The quantity given by Eq.…”

Strong terahertz emission from (100) p-type InAs

“…1 is a classic example of a polar material. The vertical lines indicate the energies of the transverse-optical ͑TO͒ and the longitudinal-optical ͑LO͒ phonons as given by Li et al 13 as 217.3 cm −1 and 238.5 cm −1 , respectively. The horizontal lines indicate the reflectivity calculated from the refractive index.…”

“…The horizontal lines indicate the reflectivity calculated from the refractive index. ͑The imaginary part k is taken to be 0.͒ The highfrequency refractive index is taken to be n = 3.5 from Li et al; 13 the low-frequency refractive index is calculated to be 3.84 using the Lyddane-Sachs-Teller relation. The observed reflectivity spectrum is consistent with these indices.…”

“…There is no evidence of the plasma above 100 cm −1 . Li et al 13 give the plasma frequency as 107 cm −1 for a sample of carrier concentration 6 ϫ 10 16 cm −3 . We conclude that the doping of the sample studied here is less than that.…”

Influence of carrier concentration on properties of InAs waveguide layers in interband cascade laser structures

“…where P 2 is the momentum matrix element of the coupling between conduction and valence bands and is assumed to be 11.9 eV 23 and m e is the electron rest mass. All the parameters required for the calculations are taken from Ref.…”