Hydrogen influence on gallium arsenide thin films prepared by rf-magnetron sputtering technique

Abstract

We investigate the effect of the hydrogen intentional incorporation on the structural properties of the amorphous gallium arsenide prepared by rf-magnetron sputtering technique. The properties of the non-hydrogenated films are: band gap of 1.4 eV (E 04 ), Urbach energy of 110 meV, stoichiometric composition ([As]/[Ga] = 0.50), and dark conductivity of about 3.2 x 10 −5 (Ω.cm) −1 . Hydrogen was incorporated in the films by the introduction of an electronically controlled H 2 flux during deposition, keeping constant the other deposition parameters. It was observed that small hydrogen incorporation produces a great change in the structural properties of the films. The main changes result from the formation of GaAs nanocrystals with mean sizes of about 7 nm into the amorphous network.

Temperature changes of the optical properties of (SiO2) n , (GaAs) m , and (SiO2) n (GaAs) m nanoparticles: Computer experiment

“…The locations of the peaks, which can be recog nized for particle IV in the second, more high fre quency half of the spectrum σ(ω), coincide with the ones for particle III. The experimental infrared spec trum of the GaAs film [23] has fundamental peaks in the low frequency half of the range under consider ation (0 ≤ ω ≤ 1600 cm -1 ), and the major peak of the infrared spectrum of α quartz [24] is located in the second (more high frequency) half of this band.…”

“…1 2013 film at Т = 300 K (curve 3) was obtained up to ω < 700 cm -1 and had two fundamental bands on the fre quencies of ~60 and 230 cm -1 [23]. These bands char acterize the acoustic and optical vibrational modes of amorphous GaAs,respectively.…”

“…3. The infrared absorption spectra for various systems: 1, nanoparticle III; 2, nanoparticle IV; 3, amorphous gallium, exper iment [23]; 4, α quartz, experiment [24].…”

“…The Raman spectra for various systems: 1, nanopar ticle III; 2, nanoparticle IV; 3, amorphous gallium, exper iment[23]; 4, α quartz, experiment[24]; 5, molten quartz, experiment[25].σ, a.u. tions of the η(ω) and κ(ω) functions are usually phase shifted.…”

Electrical transport mechanisms and structure of hydrogenated and non-hydrogenated nanocrystalline Ga1−xMnxAs films

“…The main transport in the interstitial region should be due to hopping between defect states close to the Fermi level. As the hydrogenation is expected to significantly reduce disorder and the density of the gap states in amorphous GaAs [26,27], it is expected that both the resistivity and charge trapping characteristics of these portions of the material would be significantly changed by hydrogenation. Therefore, the presence of hydrogen in this region should be a major concern in the interstitials.…”