caa a22 4500 388114770 CHVBK 20180307125403.0 cr unu---uuuuu 161130s1999 xx s 000 0 eng 10.1557/S1092578300000715 doi S1092578300000715 pii (NATIONALLICENCE)cambridge-10.1557/S1092578300000715 Skromme B.J. Department of Electrical Engineering and Center for Solid State Electronics Research, Arizona State University Photoluminescence, Magnetospectroscopy, and Resonant Electronic Raman Studies of Heteroepitaxial Gallium Nitride [Elektronische Daten] [B.J. Skromme] Optical spectroscopy, including low and room temperature photoluminescence (PL), reflectance, PL measurements in high magnetic fields up to 12 T, and resonantly-enhanced electronic Raman scattering (RERS) in zero and high magnetic field, has been used to investigate exciton and impurity states and surface recombination in high quality heteroepitaxial GaN grown on sapphire and SiC. Theoretical finite-difference calculations of the donor states as a function of magnetic field have been carried out for comparison, including the effects of anisotropy in the effective mass and dielectric constant. Up to six residual donor species are observed in material grown by hydride vapor phase epitaxy (HVPE) and metalorganic chemical vapor deposition (MOCVD) from their n=2 and n=3 two-electron satellites observed in PL and by RERS. The donor-related nature of the relevant transitions is confirmed from their magnetic field dependence, and the spectral resolution is improved at high fields. The Si donor level is determined to have a binding energy of about 21 meV from observation of its two-electron satellite in lightly Si-doped HVPE material. The free exciton binding energy is shown to be about 26.4 meV, independent of strain, based on observations of the n=2 free exciton. The room temperature band-edge PL peak is confirmed to be free excitonic in nature, based on its linewidth and on comparison with simple reflectance measurements. Reflectance from the edge of a thick HVPE layer shows clear evidence of A, B, and C excitons obeying the relevant selection rules at both low and room temperature. Surface chemical treatments are shown to have substantial effects on room temperature PL efficiency. Passivation with ammonium or sodium sulfide solutions, in particular, yields increases in PL efficiency by a factor of five to seven over air-exposed surfaces. The passivation effect is stable in air, lasting at least one month. Copyright © 1999 Materials Research Society Keywords: GaN nationallicence Si doping nationallicence optical spectroscopy nationallicence photoluminescence nationallicence reflectance nationallicence electronic Raman scattering nationallicence donors nationallicence excitons nationallicence magnetic fields nationallicence surface recombination nationallicence anisotropy nationallicence hydride vapor phase epitaxy nationallicence metalorganic nationallicence chemical vapor deposition nationallicence chemical treatment nationallicence etching nationallicence two-electron nationallicence satellites nationallicence MRS Internet Journal of Nitride Semiconductor Research Cambridge University Press 4/1(1999), e15 1092-5783 4:1<e15 1999 4 MIJ https://doi.org/10.1557/S1092578300000715 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/S1092578300000715 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Skromme B.J. Department of Electrical Engineering and Center for Solid State Electronics Research, Arizona State University NATIONALLICENCE 773 0- MRS Internet Journal of Nitride Semiconductor Research Cambridge University Press 4/1(1999), e15 1092-5783 4:1<e15 1999 4 MIJ CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge