Optical and Electrical Properties of In x Ga 1− x Se Mixed Crystal Grown from Indium Flux by Traveling Heater Method

In x Ga 1− x Se mixed crystals have been successfully grown from an indium flux by the traveling heater method at three growth temperatures. The thickness of the grown In x Ga 1− x Se mixed crystal perpendicular to (001) was more than 3 mm. The lattice constant, and optical and electrical properties of the In x Ga 1− x Se mixed crystals and undoped GaSe crystals were investigated and compared. The indium content of the In x Ga 1− x Se mixed crystals was observed to increase with decreasing growth temperature, while the lattice constant along the c -axis was observed to follow Vegard’s law. It was confirmed that a bandgap of In 0.020 Ga 0.980 Se is narrower than that of undoped GaSe according to the photoluminescence (PL) spectra. Compared with undoped GaSe crystal, the carrier concentration p was decreased by the incorporation of indium (In 0.020 Ga 0.980 Se, p = 6.4 × 10 14 cm −3 at 257 K; In 0.037 Ga 0.963 Se, p = 2.6 × 10 14 cm −3 at 257 K). In addition, it was suggested that the dominant carrier scattering mechanism of high-indium-content crystals at low temperature is ionized impurity scattering.