Superconductivity in transparent zinc-doped In₂O₃films having low carrier density

Abstract

Thin polycrystalline zinc-doped indium oxide (In 2 O 3 -ZnO) films were prepared by post-annealing amorphous films with various weight concentrations x of ZnO in the range 0 x 0.06. We have studied the dependences of the resistivity ρ and Hall coefficient on temperature T and magnetic field H in the range 0.5 T 300 K, H 6 Tfor 350 nm films annealed in air. Films with 0 x 0.03 show the superconducting resistive transition. The transition temperature T c is below 3.3 K and the carrier density n is about 10 25 -10 26 m −3 . The annealed In 2 O 3 -ZnO films were examined by transmission electron microscopy and x-ray diffraction analysis revealing that the crystallinity of the films depends on the annealing time. We studied the upper critical magnetic field H c2 (T ) for the film with x = 0.01. From the slope of dH c2 /dT , we obtain the coherence length ξ(0) ≈ 10 nm at T = 0 K and a coefficient of electronic heat capacity that is small compared with those of other oxide materials.

Reversible superconductivity in electrochromic indium-tin oxide films

“…8) and up to 3 K when combined with ZnO. 9 Further, Mori 10 reported a sharp SC transition in post-oxidized ITO films, with T c in the range 2-4 K. These results suggest that T c can be enhanced by increasing the carrier density via chemical doping. Fig.…”

Thickness and annealing effects on thermally evaporated InZnO thin films for gas sensors and blue, green and yellow emissive optical devices

“…The SEM images revealed that the grains of as-deposited and annealed films are spherical in shape and are uniformly distributed over the entire film surface [60]. The size of the grain increases with increase of annealing temperature might be due to the increase in mobility of atoms [17,61]. In addition to that, increase in annealing temperature leads to decrease in surface roughness and grain boundaries, resulted in smoothens of the film increases.…”

Superconductivity in covalent semiconductors

“…In a similar fashion, highly-doped InN and In 2 O 3 show the same T as metallic In. However, the H 2 values are very much different, and thus it was assumed that superconductivity in InN [62] and In 2 O 3 [63] is genuine. The latter conclusion has been questioned recently.…”