Optical properties of GaN epitaxial films grown by low-pressure chemical vapor epitaxy using a new nitrogen source: Hydrazoic acid (HN3)

Abstract

We report results of our growth and characterization of GaN films using low-pressure chemical vapor epitaxy with a new nitrogen source, hydrazoic acid (HN3). This growth technique allows for low-temperature deposition, low III/V ratios, and increased deposition rates (up to ∼2–3 μm/h). The deposited films show Ga:N atomic ratios of 1±0.25 based on our x-ray photoelectron spectroscopy analyses, and the He(II) UPS (ultraviolet photoelectron spectroscopy) spectra compare favorably with the semi-ab initio calculations for the GaN valence bands and with the reported UPS data for single crystal GaN films. X-ray and Raman spectra show deposited films crystallized in the expected wurtzite structure. We find these epitaxial films to be efficient light emitters in the blue or yellow region of the spectrum, depending upon growth conditions. Our photoluminescence time-decay kinetics confirm the excitonic nature of the blue emission. Lastly, far infrared time-domain spectroscopy shows the low carrier concentration of this material.

Properties of low-pressure chemical vapor epitaxial GaN films grown using hydrazoic acid (HN3)

“…32 The peaks at 5.2, 9.7, and 17.5 eV compare favorably with the results of semi ab initio calculations for the GaN valence bands 33 and with the reported UPS data taken from GaN single crystal films using 60-130 eV synchrotron radiation. 34 These three peaks could be attributed to the N 2 p, Ga 1s-np hybrid, and N 2s derived valence bands, respectively.…”

Growth of Group III Nitrides. A Review of Precursors and Techniques

“…186 Epitaxial GaN was grown with triethylgallium and HN 3 under similar conditions. 187 GaN films grown with hydrogen azide by MBE were smoother, more uniform, with no surface damage, and had greater growth rates than GaN films grown with an ECR plasma. 83 Hydrogen azide is a good nitrogen source for nitride growth but suffers from its toxic and potentially explosive nature.…”

“…Polycrystalline InN films have been grown by laser-assisted chemical vapor deposition with trimethylindium and HN 3 on Si(100) at 427 °C under low-pressure conditions . Epitaxial GaN was grown with triethylgallium and HN 3 under similar conditions . GaN films grown with hydrogen azide by MBE were smoother, more uniform, with no surface damage, and had greater growth rates than GaN films grown with an ECR plasma .…”

Model experiments on growth modes and interface electronics of CuInS2 : Ultrathin epitaxial films on GaAs(100) substrates

“…First, the upper valence band shows more structure and, in the HeII spectrum, a peak‐like structure appears at ∼12 eV. This feature is due to the Ga 3d HeII β ‐satellite . Secondly, the work function increases by about 0.8 eV to φ = 5.7 ± 0.1 eV and the valence band maximum shifts to larger values, by about 0.5 eV, to E VBM = 1.1 ± 0.1 eV.…”