Magnetotransport properties of bismuth films on p-GaAs

Polycrystalline Bi films were deposited onto p-GaAs(100) by electrochemical deposition. Annealing resulted in the formation of large grains with a preferred [012] orientation. The p-GaAs/Bi junctions were rectifying and the barrier height and ideality factor decreased with increasing film thickness. For films greater than 0.5 μm in thickness, the barrier height was about 0.56 eV and the ideality factor was between 1.1–1.2 for both as-deposited and annealed films. The resistance of the as-deposited films exhibited a negative temperature coefficient whereas the annealed films exhibited a positive temperature coefficient due to the limiting carrier mean free path. The magnetoresistance (MR) exhibited a quasilinear field dependence with an MR effect as large as 5600 (560 000%) at 5 K and 2.2 (220%) at room temperature.