INVESTIGATION OF CARBON INCORPORATION IN ZNSE - EFFECTS ON MORPHOLOGY, ELECTRICAL, AND PHOTOLUMINESCENCE PROPERTIES

Observations of carbon incorporation in epitaxial ZnSe films grown by metalorganic chemical vapor deposition are presented. Carbon is detected by secondary ion mass spectroscopy (SIMS) measurements in all ZnSe films grown from methylallylselenide and dimethylzinc. The presence of carbon in the films is correlated with a new bound excitonic emission appearing at 2.7920 eV which dominates the near-band-edge low-temperature photoluminescence spectra of all carbon contaminated films. This peak is also observed when growth is commenced from diethylselenide, under certain growth conditions, but not from hydrogen selenide. The effect of the carbon contamination is discussed in terms of variations in surface morphology, electrical and luminescence properties of as-grown films. Control of the carbon concentration is demonstrated by alternating between hydrogen selenide and methylallylselenide during growth. Strategies to avoid carbon contamination in ZnSe are also proposed. © 1990 The Mineral, Metal & Materials Society, Inc.