RF‐MBE growth of cubic InN films on MgO (001) substrates

Abstract

. Hg, 78.30.Fs, 81.15.Hi Cubic InN films have been grown on MgO substrates with cubic GaN underlayers by RF-N 2 plasma MBE. By changing the growth conditions, we clarified the growth temperature and In flux dependence of the quality of cubic InN films. It was found the surface of cubic InN films grown at relatively higher temperatures was smooth and that the hexagonal phase content in the InN films decreased with increasing In flux. Based on the findings, we have successfully obtained a c-InN film with high phase-purity and a smooth surface. We have carried out micro Raman scattering measurements for the high-quality cubic InN film. Raman peaks were clearly observed at 596 cm -1 and 467 cm -1, which are attributed to longitudinal optical and transverse optical phonon modes of cubic InN, respectively.

Photoluminescence of cubic InN films on MgO (001) substrates

“…For the contribution from optical phonon, ε ∞ is the high frequency dielectric constant, ω T and ω L are the TO and LO phonon frequency, Γ T and Γ L are the TO and LO phonon damping constants, respectively. We adopted the values for c-InN ω T = 467 cm -1 , ω L = 596 cm -1 [6]. For the contribution from interband transition, A 0 is the parameter for optical transition probability, E 0 is the band gap energy, and Γ is the broadening parameter.…”

“…Cubic III nitride semiconductors have several advantages for electronic and optoelectronic device applications compared with hexagonal ones [1], for instance, no piezoelectric nor spontaneous polarization-induced electric fields, which exist in hexagonal III nitride semiconductors and lead to the lowering of optical transition probability. Although a number of papers have reported the growth and characterization of cubic GaN (c-GaN), AlN and their alloy [2,3], the growth of cubic InN (c-InN) has been less reported [4][5][6]. Furthermore, little has been reported on the physical properties, such as band gap energy of c-InN.…”

“…Furthermore, little has been reported on the physical properties, such as band gap energy of c-InN. In our previous study [6], we successfully obtained c-InN films with high phase-purity and a smooth surface by optimizing the growth conditions, and clarified the longitudinal and transverse optical phonon energies of c-InN based on Raman scattering measurements for the high-quality films. In the present study, we report on the photoluminescence (PL) from c-InN films grown on MgO (001) substrates with c-GaN underlayers by RF-N 2 molecular beam epitaxy (MBE) and discuss the band gap energy of c-InN.…”

Metastable cubic InN layers on GaAs (001) substrates grown by MBE: Growth condition and crystal structure

“…This indicates that the cubic phase purity of the In-rich layer is considerably high. As the hexagonal phase inclusions increase to 22%, there are additional features located at the Raman shift frequencies of 491 and 585 cm -1 , corresponding to the hexagonal E 2 (high) and A 1 (LO) phonon modes, respectively [9]. The results illustrate that the hexagonal phase structure is became dominant in the N-rich c-InN layers with relatively high hexagonal phase incorporation.…”

“…For the In-rich layer with 8% hexagonal phase inclusion, two Raman scattering features with narrow FWHM of 2-4 cm -1 were clearly observed at the frequencies of 468 cm -1 and 589 cm -1 , which are attributed to the cubic transverse (TO) and longitudinal (LO) phonon modes, respectively [9]. This indicates that the cubic phase purity of the In-rich layer is considerably high.…”