Simultaneous control of the composition and the stoichiometry for a multinary new solid solution semiconductor

近年来，可调谐激光二极管的新材料受到人们的关注，其激光波长约为3.5 μ m。半导体激光器有望成为下一代光通信的光源。四元（Pb_<1-x>Cd_x）（S_<1-z>Se_z）_&lt;1+y&gt;最适合于上述目的。在这项研究中，提出了一种新的方法，同时控制组成x，z和偏离化学计量y的四元固溶体。也就是说，<1-z>通过在热处理管中提供两个储存室，在固溶体的热处理过程中独立地控制硫（Ps_2）、硒（Pse_2）和CdS_ Se_z（a_&lt;cds 1-z 'sez'&gt;）的活性。它们是硫硒混合储层和CdS储层。结果表明，CdS贮库（a_&lt;cds 1-z 'sez'&gt;）和混合贮库中S与Se的摩尔比分别对固溶体的组成x和z有重要影响。通过调节硫属元素分压之和（Ps_2+Pse_2），保持a_&lt;cds 1-z 'sez'&gt;和混合容器中硫和硒的摩尔比为对应于目标组成x和z的特定值，也可以同时控制与化学计量的偏差y。根据这一原理，成功地获得了该四元固溶体的P（Ps_2+pse_2）-T（热处理温度）-y（偏离化学计量比）图。

Attention is recently paid to the new materials for tunable laser diode, lasing at about 3.5mum. The laser diodes are expected as the light source for optical communications in the next generation. The quarternary (Pb_<1-x>Cd_x) (S_<1-z>Se_z)_<1+y> are best suited to the above purposes. In this study, a new method for simultaneously controlling the composition x,z and the deviation y from stoichiometry was proposed for the quarternay solid solution. That is, the activity of sulfur(Ps_2), selenium(Pse_2) and CdS_<1-z>Se_z(a_<cds1-z'sez'>) were controlled independently in the heat-treatment process of the solid solution by providing two reservoir chambers in the heat-treatment tube. They are the mixing reservoir of sulfur and selenium and a CdS reservoir. As a result, it was found that the composition x and z of the solid solution is seriously effected by a CdS reservoir(a_<cds1-z'sez'>) and the mole ratio of S and Se in the mixing reservoir, respectively. The deviation y from stoichiometry could also be controlled simultaneously by regulating the sum of chalcogen partial pressures (Ps_2+Pse_2), keeping a_<cds1-z'sez'> and the mole ratio of sulfur and selenium in the mixing reservoir to a specific value corresponding to the target composition x and z. Based on this principle, the diagrams of P(Ps_2+pse_2)-T(heat-treatment temperature)-y(deviation from stoichiometry) was obtained successfully for this quarternary solid solution.