Structural and optical properties of AgAlTe2 layers grown on sapphire substrates by closed space sublimation method

Abstract

AgAlTe2 layers were grown on a- and c-plane sapphire substrates using a closed space sublimation method. Grown layers were confirmed to be single phase layers of AgAlTe2 by X-ray diffraction. AgAlTe2 layers were grown to have a strong preference for the (112) orientation on both kinds of substrates. The variation in the orientation of grown layers was analyzed in detail using the X-ray diffraction pole figure measurement, which revealed that the AgAlTe2 had a preferential epitaxial relationship with the c-plane sapphire substrate. The atomic arrangement between the (112) AgAlTe2 layer and sapphire substrates was compared. It was considered that the high order of the lattice arrangement symmetry probably effectively accommodated the lattice mismatch. The optical properties of the grown layer were also evaluated by transmittance measurements. The bandgap energy was found to be around 2.3 eV, which was in agreement with the theoretical bandgap energy of AgAlTe2.

Wide Band Gap Chalcogenide Semiconductors

“…Computations predict deep extrinsic dopants Ge Al and Sn Al for use as an IBSC absorber . AgAlTe 2 has an band gap energy of ∼2.3 eV, in agreement with computational predictions, and has also garnered interest as an IBSC absorber …”

“…262 AgAlTe 2 has an band gap energy of ~2.3 eV, in agreement with computational predictions, and has also garnered interest as an IBSC absorber. 263 AgGaS 2 , with a gap of ~2.7 eV 264 , is considered a semi-insulating material due to its extremely low reported conductivity of <10 -5 S cm -1 , 265,266 though amorphous films have conductivities ~1 S cm -1 . 267 AgGaS 2 has been reported with p-type and n-type conductivity, with low doping and mobilities up to 30 cm 2 V -1 s -1 at room temperature.…”

“…277 AgAlTe 2 has an band gap energy of ∼2.3 eV, in agreement with computational predictions, and has also garnered interest as an IBSC absorber. 278 AgGaS 2 , with a gap of ∼2.7 eV, 279 is considered a semiinsulating material because of its extremely low reported p-type A few binary standards are plotted for reference (dashed lines indicate structural phase transformations), and we include some structures below 2 eV to help conceptualize the alloy space. Bowing is plotted for the binary systems to align with literature reports.…”

A Search for New Back Contacts for CdTe Solar Cells

“…AgAlTe 2 has been studied as a potential intraband solar absorber, but there is limited experimental data on the transport properties and doping. The band gap of AgAlTe 2 is 2.3 eV, [60] in agreement with our GW calculated band gap of 2.3 eV (Table S3). However, we predict that AgAlTe 2 is not highly p-type dopable; with E -E vacuum (eV) The lattice constants a and b are increased to match the lattice constant of CdTe.…”

Crystallographic and optical characterizations of Ag(Ga,Al)Te2 layers grown on c ‐plane sapphire substrates by closed space sublimation

“…Therefore, Ag(Ga,Al)Te 2 would be suitable for a novel solar cell material. AgGaTe 2 and AgAlTe 2 have been successfully grown on c-and a-plane sapphire substrates by the closed space sublimation (CSS) method, and it was shown that they had a preferential epitaxial relationship with the c-plane sapphire substrate rather than a-plane sapphire [10][11][12]. The CSS method is regarded as a low cost technique with large-area manufacturing potential because of its high throughput and efficient material consumption.…”