No abstract

We have epitaxially grown undoped b-FeSi 2 films on Si(111) substrates via atomic-hydrogen-assisted molecular-beam epitaxy. b-FeSi 2 films grown without atomic hydrogen exhibited p-type conduction with a hole density of over 10 19 cm À3 at room temperature (RT). In contrast, those prepared with atomic hydrogen showed n-type conduction and had a residual electron density that was more than two orders of magnitude lower than the hole density of films grown without atomic hydrogen (of the order of 10 16 cm À3 at RT). The minority-carrier diffusion length was estimated to be approximately 16 lm using an electron-beam-induced current technique; this value is twice as large as that for b-FeSi 2 prepared without atomic hydrogen. This result could be well explained in terms of the minority-carrier lifetimes measured by a microwave photoconductance decay technique. The 1/e decay time using a 904 nm laser pulse was approximately 17 ls, which is much longer than that for b-FeSi 2 prepared without atomic hydrogen (3 ls). The photoresponsivity reached 13 mA/W at 1.31 lm, which is the highest value ever reported for b-FeSi 2 films.

We have fabricated 200-nm-diameter ferromagnetic resonant tunneling diodes (FM-RTDs) using CaF 2 /Fe 3 Si heterostructures on Si (111)

No abstract

No abstract