Plasma damage and acceptor passivation in D2-plasma-treated InP:Zn: A photoluminescence and ellipsometry study

P. De Mierry, P. Etchegoin, M. Stutzmann

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Abstract

Deuteration of Zn-doped InP was performed by indirect exposure of the InP surface to a remote D2 glow-discharge plasma. The dopant passivation and plasma-induced defects were investigated by photoluminescence (PL) and spectroscopic ellipsometry as a function of temperature, Tpt, during plasma treatment in the range 30 220°C. It is found that low Tpt causes weak surface alteration whereas high Tpt leads to preferential etching of P and the formation of In islands. At an intermediate deuteration temperature Tpt=90°C, the surface is less affected by the plasma treatment compared to any other Tpt. In addition, a broad, low-energy PL band in the range 1.24 1.34 eV shows up. These results are explained by the in-diffusion of P vacancies (VP) created at the surface and the subsequent formation of P vacancy-related defects in the bulk of InP. Complexes such as (VP+ZnIn-) are believed to form and yield the PL band, in analogy with earlier PL studies on GaAs:Zn. The results of secondary-ion mass spectrometry and effusion measurements indicate that the diffusion of D proceeds by trapping on the Zn atoms, thus confirming the dopant passivation seen by PL measurements. In addition, the sample treated at 90°C contains a significant fraction of excess deuterium near the surface, which passivates the plasma-induced recombination centers. Additional centers are observed in InP deuterated between 90°C and 170°C. These centers can be partly annealed by laser irradiation at 77 K. The resulting strong enhancement of the low-energy PL band is interpreted as being due to the rearrangement of VP-related recombination centers into VP-related radiative centers assumed to be VP+ ZnIn-.

Original languageEnglish
Pages (from-to)5283-5290
Number of pages8
JournalPhysical Review B
Volume49
Issue number8
DOIs
StatePublished - 1994
Externally publishedYes

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