Direct and fast growth of GaAs thin films on glass and polyethylene terephthalate substrates using a thermionic vacuum arc

Abstract

Using a thermionic vacuum arc, single-crystal gallium arsenide (GaAs) layers of micron thickness were grown on PET and glass substrates in 2 min. We present a new deposition mechanism and parameters for GaAs thin films produced in a very short time. Crystal direction was found to be (111) plane for the GaAs/PET sample and (022) plane and (133) plane for the GaAs/glass sample, respectively. The average roughness values of the deposited thin films were determined to be approximately 30 nm for GaAs/PET and 60 nm for GaAs/glass. The structures can be seen clearly in field emission scanning electron microscopy and atomic force microscopy. The obtained optical band is nearly the same with literatures values of the GaAs. Although produced structures in different crystal formations, only aggregations dimensions and absorbance of the layers were changed. Obtained refractive index values are nearly same with database info.

Some physical properties of a Si-doped nano-crystalline GaAs thin film grown by thermionic vacuum arc

“…The refractive index of the film which was observed to be higher than the reported refractive index value of the GaAs films in Ref. [22] decreased from 3.90 to 3.82 with the increasing wavelength. The extinction coefficient also decreased with increasing wavelength and reset to zero when the wavelength was larger than 800 nm.…”

“…This value was observed to be lower than the E g value of the GaAs films in Ref. [22]. Tauc's approximation is quite reliable though it might be not totally correct.…”

“…When compared to the FESEM images presented in Ref. [22], the grain size tended to be smaller with Si doping. Fig.…”

“…However, the doping characteristics strongly depend on the nature of the applied growth technique. Undoped and doped GaAs thin films have been deposited by various techniques such as chemical vapor deposition [2], metal organic chemical vapor deposition [15e17], molecular beam epitaxy [4,18,19], RF magnetron sputtering [20], laser ablation [21] and thermionic vacuum arc (TVA) [22].…”

Optical and surface properties of the in doped GaAs layer deposition using thermionic vacuum arc method

“…The band gap energy of the In x Ga 1‐x As varies between 0.50 eV and 1.00 eV. x value is varied between 0.07 and 0.77 (Schapers et al ., ; Parker et al ., ; Zhuang et al ., ; Metzger et al ., ; Pat et al ., ). Obtained band gap values are very close to literatures values.…”