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Synthesis of Highly Anisotropic Semiconducting GaTe Nanomaterials and Emerging Properties Enabled by Epitaxy

Cai, H and Chen, B and Wang, G and Soignard, E and Khosravi, A and Manca, M and Marie, X and Chang, SLY and Urbaszek, B and Tongay, S (2017) Synthesis of Highly Anisotropic Semiconducting GaTe Nanomaterials and Emerging Properties Enabled by Epitaxy. Advanced Materials, 29. p. 1605551. ISSN 0935-9648

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Abstract

GaTe flakes were synthesized by the PVT technique in a tube furnace using GaTe and Ga2Te3 polycrystalline powders as the source. The PVT synthesis of GaTe flakes was carried out in a tube furnace with a 1'' quartz tube. GaTe and Ga2Te3 powders were mixed together as the source materials, and Ar (15 sccm)+H2 (5 sccm) was used as the carrier gas. GaAs, Si, and c-cut sapphire wafers were used as growth substrates. Prior to growth the GaAs substrates were cleaned by piranha solution followed by dilute hydrogen chloride (HCl) solution. The source powders were loaded in a quartz boat and sent to the center of the tube. The substrate was located 10 cm away downstream. The temperature was kept at 650°C for 5 min and then cooled down to room temperature. The Ar flow rate was set at 15 sccm and the growth pressure was 30 Torr for the whole process. The GaTe bulk crystals were synthesized by the modified Bridgman growth technique in a single zone furnace at temperatures ranging from 850 to 1020°C for three weeks. Room temperature PL and Raman measurements for the GaTe flakes were performed. Interestingly, nanomaterials grown on sapphire exhibit well-defined, narrow, and bright PL emission peaks originating from localized emission due to a select type of imperfection site states that appear at energies well below the fundamental emission line (optical band gap). Bright emission within the forbidden band is observed for the first time in GaTe and may be the starting point for further defect engineering for optoelectronics in PTMCs. Lastly, angle-resolved PL and Raman studies suggest that the synthesized monoclinic GaTe flakes are also highly anisotropic due to their unique crystal structure, which is the first demonstration of the anisotropy in vapor phase synthesized pseudo 1D GaTe.

Item Type: Article
Uncontrolled Keywords: gallium telluride physical vapor transport pseudo-1D materials
Subjects: UNSPECIFIED
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 20:04
Last Modified: 13 Apr 2021 10:30
DOI: 10.1002/adma.201605551