Kim Sangsu, Kim Deok, Hong Jinki, Elmughrabi Abdallah, Melis Alima, Yeom Jung-Yeol, Park Chansun, Cho Shinhaeng
Department of Display and Semiconductor Physics, Sejong Campus, Korea University, 2511 Sejong-ro, Sejong City 30019, Korea.
Department of Radiation Oncology, Chonnam National University Medical School, 160 Baekseo-ro, Gwangju 61469, Korea.
Materials (Basel). 2022 Feb 14;15(4):1408. doi: 10.3390/ma15041408.
We compared thermal stability, open-circuit voltage, short-circuit current, and fill factor values of single-crystal Cadmium telluride (CdTe) grown using the vertical Bridgman (VB) technique and doped with group V elements (phosphorus and arsenic), and group Ⅰ element (sodium), followed by an annealing process. The sodium-doped CdTe maintained a hole density of 10 cm or higher; after annealing for a long time, this decreased to 10 cm or less. The arsenic-doped CdTe maintained a hole density of approximately 10 cm even after the annealing process; however its bulk minority carrier lifetime decreased by approximately 10%. The phosphorus-doped CdTe maintained its properties after the annealing process, ultimately achieving a hole density of ~10 cm and a minority carrier lifetime of ~40 ns. The characteristics of a single-crystal solar cell were evaluated using a solar cell device that contained single-crystal CdTe with various dopants. The sodium-doped sample exhibited poor interfacial properties, and its performance decreased rapidly during annealing. The samples doped with group V elements exhibited stable characteristics even during long-term annealing. We concluded, therefore, that group V elements dopants are more suitable for CdTe single-crystal-based solar cell applications involving thermal stress conditions, such as space missions or extreme fabrication temperature environments.
我们比较了采用垂直布里奇曼（VB）技术生长、掺杂Ⅴ族元素（磷和砷）以及Ⅰ族元素（钠）并经过退火处理的单晶碲化镉（CdTe）的热稳定性、开路电压、短路电流和填充因子值。钠掺杂的CdTe保持了10¹⁵ cm⁻³或更高的空穴密度；长时间退火后，该密度降至10¹⁵ cm⁻³或更低。砷掺杂的CdTe即使在退火处理后仍保持约10¹⁵ cm⁻³的空穴密度；然而其体内少数载流子寿命降低了约10%。磷掺杂的CdTe在退火处理后保持其性能，最终实现了约10¹⁵ cm⁻³的空穴密度和约40 ns的少数载流子寿命。使用包含具有各种掺杂剂的单晶CdTe的太阳能电池器件评估了单晶太阳能电池的特性。钠掺杂的样品表现出较差的界面性能，并且其性能在退火期间迅速下降。掺杂Ⅴ族元素的样品即使在长期退火期间也表现出稳定的特性。因此，我们得出结论，Ⅴ族元素掺杂剂更适合用于涉及热应力条件的基于CdTe单晶的太阳能电池应用，如太空任务或极端制造温度环境。
