Estimation of interaction parameters in the Al-Ga-As-Sn-Bi system

Vladimir Khvostikov; Olga Khvostikova; Nataliia Potapovich; Alexey Vlasov; Roman Salii

doi:10.1016/j.heliyon.2023.e18063

Estimation of interaction parameters in the Al-Ga-As-Sn-Bi system

Heliyon. 2023 Jul 7;9(7):e18063. doi: 10.1016/j.heliyon.2023.e18063. eCollection 2023 Jul.

Authors

Vladimir Khvostikov¹, Olga Khvostikova¹, Nataliia Potapovich¹, Alexey Vlasov¹, Roman Salii¹

Affiliation

¹ Ioffe Institute, Politechnicheskaya 26, St. Petersburg, 194021, Russia.

Abstract

The development of GaAs based high power side-input photovoltaic converters requires thick (50-100 μm) transparent gradient refraction layers that can be grown by liquid phase epitaxy. Such thick layers can also be used in LED structures. To solve the problem of Al_xGa_1-xAs conductivity reduction at the x∼40% point a five-component, Al-Ga-As-Sn-Bi system is proposed. The interaction parameters in the liquid phase (αij) in the Al-Ga-As-Sn-Bi system are determined within the framework of a quasi-regular solutions model. For an Al_xGa_1-xAs solid solution growing from a Ga-melt containing 10 at.% of Bi (as a neutral solvent) and 15 at.% of Sn (as an n-type dopant), liquidus and solidus isotherms for 900 °C are modeled based on the calculated αij. Satisfactory agreement between calculated and experimental data has been obtained. Hall data show that AlGaAs layers grown from Bi-containing melts have n-type conductivity. Doping by tin during growth from mixed Ga-Bi melts makes it possible to increase the electron concentration in the AlGaAs layer.

Keywords: Crystal growth; Ga–Bi melt; Hall data; Thermodynamic modeling.