Epitaxial diodes of a half-metallic ferromagnet on an oxide semiconductor

Abstract

We report on the fabrication and electrical characterization of epitaxial Schottky diodes of a half-metallic ferromagnet on an oxide semiconductor. La0.67Sr0.33MnO3 thin films are grown by pulsed laser deposition on niobium-doped SrTiO3 semiconductor substrates with two doping concentrations and a TiO2 surface termination. The current across the diodes is dominated by thermionic emission and shows high rectification and low reverse bias leakage. At room temperature, the Schottky barrier height is 0.95 eV (0.65 eV) and the ideality factor is 1.08 (1.18) for the diodes with a low (high) doped semiconductor. With decreasing temperature the Schottky barrier height decreases and the ideality factor increases.

Hysteretic current–voltage characteristics and resistance switching at an epitaxial oxide Schottky junction SrRuO3∕SrTi0.99Nb0.01O3

“…13 In all cases, the rectification direction is consistent with that of a Schottky junction with regarding Sr(Ti,Nb)O 3 and metallic perovskites as n-type semiconductor and deep work-function metals, respectively. The present SrRuO 3 /Sr(Ti,Nb)O 3 junction is considered to be one of them.…”

Thermally assisted tunneling transport in La0.7Ca0.3MnO3/SrTiOCuellar1, Sánchez-Santolino2, Varela3 et al. 2012Phys. Rev. B200110View full textAdd to dashboardCite

“…Similar deviations of the current-voltage characteristics from an ideal thermionic emission have been previously reported in heterojunctions of NSTO with other transitionmetal oxides, [7][8][9][10]26 and thermionic-field emission (thermally assisted tunneling) has been proposed as a possible mechanism that may explain the observed results. 8 In particular, as described below in more detail, a thermionic-field emission process would explain the almost temperature-independent slope observed in log 10 J − V curves at low temperatures [see Fig.…”

“…8,30 The small values could result from the high electric field existing in the space-charge region, 31 or from the presence of a low-permittivity layer at the NSTO surface. 7,32 Interestingly, although ε r was considered to be temperature independent in previous analyses of similar J − V characteristics, capacitance measurements indicated that ε r has a temperature dependence similar to the one we obtain here. 8 Note also that in order to obtain the dielectric permittivity values, we used Eq.…”

“…Interface band profiles in several complex oxide heterojunctions have been previously investigated by optical spectroscopy 5 and transport measurements 6 in order to gain a basic knowledge of the electronic reconstruction at the interface between complex oxides and the differences from interfaces in conventional semiconductor heterojunctions. In particular, the manganite-titanate interface has been the focus of considerable research interest, [7][8][9][10][11][12][13][14] and very recently the engineering of the interface dipole has allowed the design of a perovskite oxide-based transistor. 15 Here we report on the fabrication and electrical transport characterization of La Ca manganite doped titanate heterojunctions La 0.7 Ca 0.3 MnO 3 /SrTiO 3 :Nb, with lateral size of just a few micrometers.…”

Probing electron transport across a LSMO/Nb:STO heterointerface at the nanoscale

“…Similar observations of a decrease in SBH and an increase in the ideality factor at low temperatures have also been reported for different combinations of manganite/Nb:STO interfaces. [19][20][21] Hot electron transmission, recorded using BEEM, across a LSMO (13 u.c. )/Nb:STO Schottky interface is shown in Fig.…”