Photoreflectance study of exciton energies and linewidths for homoepitaxial and heteroepitaxial GaN layers

Kudrawiec, R.; Rudzinski, M.; Serafinczuk, J.; Polish_hook, M.; Misiewicz, J.
May 2009
Journal of Applied Physics;May2009, Vol. 105 Issue 9, p093541
Academic Journal
Photoreflectance has been applied to study the exciton energies and linewidths for hetero- and homoepitaxial GaN layers (i.e., GaN layers grown on sapphire and truly bulk GaN crystal obtained by ammonothermal method). In order to modulate the built-in electric field inside the samples and eliminate photoluminescence signal from photoreflectance spectra, the surface band bending was modulated by the laser light with the photon energy smaller than the energy gap of GaN, i.e., a 532 nm laser line. The Varshni-type and Bose–Einstein-type parameters that describe the temperature dependence of the exciton transition energies have been evaluated and compared for the two GaN epilayers. It has been concluded that the residual strain in the heteroepitaxial layer influences the exciton transition energy but does not influence the Varshni and Bose–Einstein parameters. It has been found that this strain significantly influences the exciton linewidth. The broadening parameter, which is associated with the temperature-independent mechanisms (Γ0 parameter corresponding to the exciton linewidth at 0 K), has been found to be ∼1 meV for the homoepitaxial layer. For the heteroepitaxial layer this parameter is twice higher (this work) or few times higher (previous papers).


Related Articles

  • Radiative recombination life time of an exciton confined in a strained wide band gap quantum dot. Revathi, M.; Peter, A. John // AIP Conference Proceedings;6/5/2012, Vol. 1447 Issue 1, p1035 

    The behaviour of exciton binding energy and the radiative life time of exciton in a strained GaN/Ga1-xAlxN cylindrical quantum dot are investigated with and without the effect of built-in electric field. Built-in electric field due to piezoelectricity and spontaneous polarization and the...

  • Strong light-matter coupling at room temperature in simple geometry GaN microcavities grown on silicon. Semond, F.; Sellers, I. R.; Natali, F.; Byrne, D.; Leroux, M.; Massies, J.; Ollier, N.; Leymarie, J.; Disseix, P.; Vasson, A. // Applied Physics Letters;7/11/2005, Vol. 87 Issue 2, p021102 

    The reflectance spectra of simple design GaN-based microcavities have been studied in the 5 K–300 K range. The epitaxial structure consists of the silicon substrate and the stack of buffer layers as the back mirror, a GaN active layer, and a 100 Å thick aluminium layer as the top...

  • Electron traps in Ga(As,N) layers grown by molecular-beam epitaxy. Krispin, P.; Spruytte, S. G.; Harris, J. S.; Ploog, K. H. // Applied Physics Letters;3/25/2002, Vol. 80 Issue 12, p2120 

    Deep levels in the upper half of the band gap of strained Ga(As,N) with a GaN mole fraction of 3% are examined by deep-level transient Fourier spectroscopy on GaAs/Ga(As,N)/GaAs heterojunctions grown by molecular-beam epitaxy. In as-grown structures, we find a dominant electron trap at 0.25 eV...

  • Temperature-controlled epitaxy of InxGa1-xN alloys and their band gap bowing. Liu, S. T.; Wang, X. Q.; Chen, G.; Zhang, Y. W.; Feng, L.; Huang, C. C.; Xu, F. J.; Tang, N.; Sang, L. W.; Sumiya, M.; Shen, B. // Journal of Applied Physics;Dec2011, Vol. 110 Issue 11, p113514 

    InxGa1-xN alloys (0 ≤ x ≤ 1) have been grown on GaN/sapphire templates by molecular beam epitaxy. Growth temperature controlled epitaxy was proposed to modulate the In composition so that each InxGa1-xN layer was grown at a temperature as high as possible and thus their crystalline...

  • Electrical field effect of H-implantation induced defect states in GaN. Krtschil, A.; Kielburg, A.; Witte, H.; Krost, A.; Christen, J.; Wenzel, A.; Rauschenbach, B. // Applied Physics Letters;1/20/2003, Vol. 82 Issue 3, p403 

    Gallium nitride layers grown by metalorganic vapor phase epitaxy on sapphire substrates were implanted with 20 keV hydrogen ions with fluences between 2 × 10[SUP14] and 2 × 10[SUP15]ions per cm[SUP2]. The resulting deep level spectrum was analyzed by deep level transient as well as by...

  • Photoreflectance spectra of excitonic polaritons in GaN substrate prepared by lateral epitaxial overgrowth. Chichibu, S. F.; Torii, K.; Deguchi, T.; Sota, T.; Setoguchi, A.; Nakanishi, H.; Azuhata, T.; Nakamura, S. // Applied Physics Letters;3/20/2000, Vol. 76 Issue 12, p1576 

    Photoreflectance (PR) spectra of high-purity, nearly free-standing GaN substrate were compared with emission and reflectance spectra, which were analyzed based on a model exciton-polariton picture in which A, B, and C free excitons couple simultaneously to an electromagnetic wave. The GaN...

  • Radiation-induced defects in GaN bulk grown by halide vapor phase epitaxy. Tran Thien Duc; Pozina, Galia; Nguyen Tien Son; Janzén, Erik; Takeshi Ohshima; Hemmingsson, Carl // Applied Physics Letters;9/8/2014, Vol. 105 Issue 10, p1 

    Defects induced by electron irradiation in thick free-standing GaN layers grown by halide vapor phase epitaxy were studied by deep level transient spectroscopy. In as-grown materials, six electron traps, labeled D2 (EC-0.24eV), D3 (EC-0.60eV), D4 (EC-0.69eV), D5 (EC-0.96eV), D7 (EC-1.19eV), and...

  • H-point exciton transitions in bulk MoS2. Saigal, Nihit; Ghosh, Sandip // Applied Physics Letters;5/4/2015, Vol. 106 Issue 18, p1 

    Reflectance and photoreflectance spectrum of bulk MoS2 around its direct bandgap energy have been measured at 12 K. Apart from spectral features due to the A and B ground state exciton transitions at the K-point of the Brillouin zone, one observes additional features at nearby energies. Through...

  • Band gaps and internal electric fields in semipolar short period InN/GaN superlattices. Gorczyca, I.; Skrobas, K.; Suski, T.; Christensen, N. E.; Svane, A. // Applied Physics Letters;6/9/2014, Vol. 104 Issue 23, p1 

    The electronic structures and internal electric fields of semipolar short-period mInN/nGaN superlattices (SLs) have been calculated for several compositions (m, n). Two types of SL are considered, (1122) and (2021), corresponding to growth along the wurtzite s2 and s6 directions, respectively....


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics