Measurement of Diffusion Lengths in Direct-Gap Semiconductors by Electron-Beam Excitation

Abstract

In semiconductors having high efficiency for radiative recombination, the voltage dependence of cathodoluminescence may be used to determine the diffusion length and to estimate the surface recombination velocity of excess carriers. Theoretical calculations are based on a knowledge of the Laplace transform of the distribution of excitation with depth as determined from the target absorption correction in electron probe microanalysis or, alternatively, on a Gaussian approximation to the distribution of excitation with depth. Experimental results with accelerating voltages of 5–50 kV indicate values of diffusion length in n-type GaAs ranging from 3.0 μ at low-carrier concentration (5.1×1016 cm−3) to 0.65 μ at high-carrier concentration (3×1018 cm−3). The estimated accuracy for diffusion lengths between 0.5 and 4 μ is ±30%. Information is also obtained on the surface recombination velocity and the thickness of a ``dead layer'' at the surface.

Monte Carlo Study of the Interaction Volume Changes by the Beam Skirt in VP-SEM

“…3 and Fig. 4 and are consistent with theoretical predictions [17][18][19][20][21]. Concretely, in the case of maximum depth (Fig.…”

“…1) by monitoring the behavior of electrons in gas and in material at the same time is developed. Our results have been compared with theoretical values in literature for high vacuum mode that give depth and width of electrons penetration in solid [17][18][19][20][21]. Figure 1 shows three cases corresponding to three values of the energy of the electron beam E1, E2, and E3 (E1 < E2 < E3).…”

Modifications of the electronic structure of GaSb surface by chalcogen atoms: S, Se, and Te

“…In most cases, the photoluminescence yield can be simply related to the thickness of the surface depletion region and the surface recombination velocity. 17,18 The variation of the PL intensity from n-GaSb after chalcogen treatments in aqueous and nonaqueous solutions are listed in Table I. The values are the average of multiple separately treated samples and are referenced to the control sample.…”

Nanowire based heterostructures: fundamental properties and applications

“…17,18 An optically inactive layer at the semiconductor surface can be the consequence. 19 Such phenomena will be most pronounced for thin nanowires where the surface to volume ratio increases.…”