Galvanomagnetic Studies of Bismuth Films in the Quantum-Size-Effect Region

Structural and magneto-transport properties of electrodeposited bismuth nanowires

“…In pure bulk Bi single crystals, large values of MR have been observed at 4.2 K. 17 However, in thin films, other than the molecular-beam epitaxy grown epitaxial Bi single crystals, 16,18 the magnitude of the MR effect is generally much less. 14,19 As shown in this work, very large MR effect can be realized in arrays of Bi nanowires, fabricated by electrodeposition. The structural study by TEM has revealed that the Bi nanowires essentially consist of large grains along the wire direction.…”

“…For example, the pursuit of quantum effects such as the semimetal-semiconductor transition in Bi thin films has continued to attract attention. [14][15][16] To date, most of the Bi nanostructures are in thin film form. However, fabrication of high quality Bi thin films through traditional vapor deposition has proven to be technically challenging.…”

“…In bulk Bi, the TCR is positive, while negative TCR is usually observed in Bi thin films. [14][15][16] This is because the main contributions to the TCR in Bi are due to carrier concentration and mobility, which have opposite temperature dependence. With increasing temperatures, the carrier concentration increases, whereas the carrier mobility decreases, leading to respectively a negative and a positive TCR.…”

Giant positive magnetoresistance of Bi nanowire arrays in high magnetic fields

“…In thin films, however, l(T) has less temperature dependence so that n(T) has a larger effect on R(T). 8 In our nanowire arrays, the increase of resistance at low temperatures shown in Fig. 1 indicates that l(T) is cut off in the wires as well, that n(T) also determines R(T) in our samples.…”

Very large magnetoresistance in electrodeposited single-crystal Bi thin films (invited)

“…12 The effective carrier mass m* and the con- The earlier simple analyses show that very large MR effects can be observed in Bi samples with a very long mean free path l. This has been realized in bulk Bi single crystals with l in excess of 100 m that show MR as much as 10 6 times at low temperatures. 11 Due to its unusual electronic properties ͑e.g., very long Fermi wavelength of 400 Å͒ 13 and a long l, Bi is also a unique medium for exploring quantum and ballistic transport properties. [14][15][16] For such studies as well as for capturing the large MR effect for technological purposes, Bi in thin film form is required.…”