Shubnikov-de Haas Effect in Lithium-Diffused Tellurium-Doped n -Type Gallium Antimonide

Shubnikov-de Haas oscillations in magnetoresistance have been observed in low-concentration n-type tellurium-doped gallium antimonide after lithium diffusion. The Fermi energies of the samples investigated lie between {~}0.03 and {~}0.05 eV above the k=0 conduction-band minimum. Since the energy difference between the k=0 minimum and subsidiary $〈111〉$ minima is {~}0.08 eV at 4.2^∘{}K, the oscillatory effect is due solely to carriers in the k=0 valley. The oscillatory behavior has been investigated over the temperature range 1.3 to 20.4^∘{}K in magnetic fields up to 29 KG. The carrier concentration derived from the period of oscillation is in good agreement with Hall-coefficient results. Analysis of oscillatory amplitude as a function of temperature for the lithium-diffused samples yields a smaller effective mass than was observed earlier for as-grown tellurium-doped material with a Fermi energy {~}0.08 eV above the k=0 minimum. The result is shown to be consistent with the nonparabolicity predicted by a Kane conduction-band model for the k=0 band. Nonthermal broadening is primarily collision broadening.