Showing papers by "Simon Brown published in 1999"
TL;DR: In this paper, the authors observed metastable defects associated with both the yellow and blue bands of gallium nitride and showed that these defects are associated with a striking transition from a dominant blue luminescence band to a dominant yellow luminance band.
Abstract: Gallium nitride has been reactive-ion etched with SF6 and argon plasmas. The Ar-etched samples show a striking transition from a dominant blue luminescence band to a dominant yellow luminescence band after less than 5 min of low power illumination. The observation of metastable defects which are associated with both the yellow and blue bands has important consequences for our understanding of defect-related luminescence in gallium nitride.
39 citations
TL;DR: In this article, GaN grown on c-plane sapphire substrates has been reactive ion etched successfully in a SF6 plasma with an etch rate of 29 nm/min.
Abstract: GaN grown on c-plane sapphire substrates has been reactive ion etched successfully in a SF6 plasma with an etch rate of 29 nm/min. The etch rate does not change with substrate temperatures between 10 and 50 °C. Optical transitions have not been destroyed after etching, instead, two additional lower energy transitions appear close to the band-edge luminescence. The two additional transitions are related to defect states that bind excitons. The defect-bound states exhibit different behavior compared to the free excitonic states in that their normalized intensities decrease more rapidly as temperature increases, the peaks exist only up to 80 K, and their line energies show no temperature dependence.
29 citations
TL;DR: In this paper, a process using electron beam lithography and reactive ion etching for the high-resolution pattern transfer of GaN was developed, and 150 nm dots have been fabricated in GaN successfully.
Abstract: We have developed a process using electron beam lithography and reactive ion etching for the high resolution pattern transfer of GaN. 150 nm dots have been fabricated in GaN successfully. Photoluminescence, scanning electron microscopy, and x-ray photoelectron spectroscopy have been employed to compare the damage inflicted on the GaN surfaces after SF6 and Ar plasma exposures. Near-band-edge luminescence analysis indicates the existence of a higher concentration of donors on the top 100 nm of the GaN surface after Ar as supposed to SF6 plasma exposure. An order of magnitude decrease in the ratio of the yellow to the band-edge luminescence intensity is found in the samples subjected to lower ion energies. Formation of pits is observed on the substrate surfaces after plasma treatment. Nitrogen deficient surfaces limited to the top few monolayers, as well as defect propagation down to 100 nm, exist in our plasma exposed GaN samples.
23 citations