Precipitation control and activation enhancement in boron-doped p + -BaSi2 films grown by molecular beam epitaxy
2014; American Institute of Physics; Volume: 104; Issue: 25 Linguagem: Inglês
10.1063/1.4885553
ISSN1520-8842
AutoresM. Ajmal Khan, Kotaro Nakamura, Wenjie Du, Kaoru Toko, Noritaka Usami, Takashi Suemasu,
Tópico(s)Chalcogenide Semiconductor Thin Films
ResumoPrecipitation free boron (B)-doped as-grown p+-BaSi2 layer is essential for the BaSi2 p-n junction solar cells. In this article, B-doped p-BaSi2 layers were grown by molecular beam epitaxy on Si(111) substrates, and the influence of substrate growth temperature (TS) and B temperature (TB) in the Knudsen cell crucible were investigated on the formation of B precipitates and the activation efficiency. The hole concentration, p, reached 1.0 × 1019 cm−3 at room temperature for TS = 600 and TB = 1550 °C. However, the activation rate of B was only 0.1%. Furthermore, the B precipitates were observed by transmission electron microscopy (TEM). When the TS was raised to 650 °C and the TB was decreased to 1350 °C, the p reached 6.8 × 1019 cm−3, and the activation rate increased to more than 20%. No precipitation of B was also confirmed by TEM.
Referência(s)