This paper examines the damage created by an electron beam on layered specimens consisting of a (CH2)17 self-assembled monolayer (SAM) deposited on an oxidized Si wafer. Beam effects on both the SAM and substrate were observed. X-ray photoelectron spectroscopy (XPS) measurements indicate that less than 20% of the carbon from the film is lost during the beam damage, ion analysis shows hydrogen emission from the films, and residual gas analysis suggest loss of some CHx (x=2–4) molecules. Consistent with the conversion of some (CH)n chains to ‘‘graphite,’’ the C 1s photopeak is broadened by the electron beam. In addition to the effects on the SAM layer, there are shifts for the O 1s and oxidized-Si2p binding energies due to the electron beam exposure. Studies on SiO2 films formed in a wide variety of ways, without the SAM, show similar effects. These shifts are attributed to changes in potential at the Si–SiO2 interface.

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Photoluminescence (PL) results from a novel modulation doped AlGaAs/ low-temperature molecular beam epitaxially-grown-GaAs (LT-GaAs MODFET) heterostructure are reported. A new PL line at 1.65 eV is consistently observed in all the LT-GaAs MODFET structures investigated. A spatially indirect transition from a two-dimensional electron gas at the heterojunction interface to the holes in AlGaAs is believed to be responsible for the observed 1.65 eV PL line. LT-GaAs MODFET structures in which LT-GaAs region is grown at 350 °C show additional lines lying in the band edge region as well as deep inside the band gap region of LT-GaAs.

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