Growth of high‐quality hexagonal InN on 3C‐SiC (001) by molecular beam epitaxy

We have investigated the growth of InN films by plasma assisted molecular beam epitaxy on the Si-face of 6H-SiC(0001). Growth is performed under In-rich conditions using a two-step process consisting of the deposition of a thin, low-temperature 350 °C InN buffer layer, followed by the subsequent deposition of the InN epitaxial layer at 450 °C. The effect of buffer annealing is investigated. The structural and optical evolution of the growing layer has been monitored in real time using RHEED and spectroscopic ellipsometry. Structural, morphological, electrical and optic properties are discussed.1 Introduction InN is a very attractive material for future optical and electronic devices. This is because of its outstanding material properties such as the smallest effective mass, largest mobility, highest peak and saturation velocities, and smallest direct band gap in family of nitride semiconductors. To date, InN has been the least studied of the III-nitride materials because of the difficulty in growing goodquality InN without excess In or In droplets on the surface, or polycrystallinity. The bandgap of InN has long been thought to be approximately 1.9 eV. Recently, various values of the optical band gap from 0.7 eV to 1.7 eV have been correlated with the measured free electron concentration [1]. Progress has been made in the growth of high-quality InN. InN is being grown predominantly by molecular beam epitaxy (MBE) on sapphire using AlN [2,3] Herein, we report on the plasma assisted MBE growth of InN films on 6H-SiC substrates using a twostep process consisting of the deposition of a thin low-temperature InN layer followed by its annealing and subsequent deposition of the epitaxial layer. We discuss the impact of the In-rich deposition conditions and of the annealing of the InN buffer on the structural, morphological, optical and electrical properties of films, which were characterized by X-ray diffraction, atomic force microscopy, spectroscopic ellipsometry (both ex-situ and in-situ), and Hall effect measurements. We show that optimisation of annealing of the low-temperature InN nucleation layer, preventing its decomposition, yields an InN nucleation layer completely wetting the SiC substrate, which results in improvement of InN epitaxial layer.

Section: Epitaxial Layersupporting

confidence: 80%

Growth of InN on 6H‐SiC by plasma assisted molecular beam epitaxy

Brown

Kim

Choi

et al. 2006

“…The weaker PL peak observed at 0.47 eV can be attributed to the emission from the c-InN phase, as will be discussed below. It should be noted that the PL peak at 0.47 eV was not observed for our hexagonal InN (h-InN) films [8]. On the other hand, the stronger PL peak at 0.69 eV corresponds to the emission from the h-InN phase slightly included in the film.…”

Section: Resultsmentioning

confidence: 80%

“…The weak emission at 0.47 eV indicates that the crystal quality of c-InN is considerably low in comparison with h-InN obtained in this study. We found the intensity of the PL peak at 0.69 eV of this sample was ~1/20 of that of the PL peak of a h-InN film [8], which is reasonable taking into consideration the volume fraction. This expression for dielectric function is the sum of contributions from optical phonon and 3-dimensional M 0 interband transition [9].…”

Section: Resultsmentioning

confidence: 90%

Photoluminescence of cubic InN films on MgO (001) substrates

Inoue

Iwahashi

Oishi

et al. 2008

We have studied photoluminescence from cubic InN films grown on MgO substrates with a cubic GaN underlayer by RF N2 plasma molecular beam epitaxy. A single PL peak was observed at 0.47 eV. By analyzing the reflectance spectra of cubic InN films, we could derive the refractive index and extinction coefficient, and found the band gap energy of cubic InN is 0.48 eV, indicating that the PL peak observed at 0.47 eV is due to the interband transition of cubic InN. The difference in the PL peak energy between hexagonal and cubic InN is in good agreement with that predicted by ab‐initio calculations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

“…Although sapphire substrates have been widely used for the growth of InN, SiC is an attractive alternate because of its electrical conduction and high thermal conductivity, which are helpful for device applications. We have previously reported molecular beam epitaxy growth of high-quality hexagonal InN (h-InN) films on 3C-SiC (001) substrates with h-InN (0001) || 3C-SiC (001) and h-InN (1-100) || 3C-SiC (110) utilizing the small mismatch between h-InN (1-100) and 3C-SiC (110) [2]. In addition, we have reported the growth of InN/InGaN multiple quantum well (MQW) structures on 3C-SiC (001) substrates [3].…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence study of hexagonal InN/InGaN quantum well structures grown on 3C‐SiC (001) substrates by molecular beam epitaxy

Hirano

Inoue

Shikata

et al. 2008

We have studied photoluminescence from hexagonal InN/InGaN multiple quantum well structures grown on 3C‐SiC (001) substrates with an InGaN underlayer by plasma assisted molecular beam epitaxy. We have observed photoluminescence spectra of InN/InGaN MQWs with various well widths. The photoluminescence peak related to quantum wells was clearly observed even at room temperature and found to shift to higher energies with decreasing well width due to the quantum confinement effect. We also discuss the effect of the built‐in electric fields on the PL peak energy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)