Bridgman 방법으로 성장된 $TlGa_xIn_{1-x}Se_2$ 단결정의 격자상수와 energy gap의 성분의존성을 조사하였다. $TlGa_xIn_{1-x}Se_2$ solid solution의 불연속 특성이 tetragonal과 monoclinic 구조를 가진 0.25<X<0.65의 성분영역에서 일어났으며, tetragonal 구조($0.0{leq}X{leq}0.25$)로부터 monoclinic 구조($0.65{leq}X{leq}1.0$)로 변하는 구조적 상전이가 이 성분영역에서 관측되었다. $TlGaSe_2$ 단결정의 energy gap과 유전상수의 온도의존성으로부터 각각 1차 및 2차 상전이에 상당하는 107 K와 120 K에서 변칙특성을 발견하였다.
An investigation was made of the dependences of the lattice constants and the energy gap on the composition of $TlGa_xIn_{1-x}Se_2$ single cystals grown by Bridgman method. It was found that a discontinuity in $TlGa_xIn_{1-x}Se_2$ solid solutions occurred in the composition range 0.25<X<0.65 with both tetragonal and monoclinic structure. Consequently, the structural phase transition from the tetragonal structure ($0.0{leq}X{leq}0.25$) to the monoclinic structure ($0.65{leq}X{leq}1.0$) was observed in this composition range. The temperature dependences of the energy gap and the dielectric constant in $TlGaSe_2$ single crystal have shown that the anomalies appeared at 107 K and 120 K corresponding to first-order and second-order phase transitions, respectively.
