Current–voltage characteristics of manganite–titanite perovskite junctions

Abstract

SummaryAfter a general introduction into the Shockley theory of current voltage (J–V) characteristics of inorganic and organic semiconductor junctions of different bandwidth, we apply the Shockley theory-based, one diode model to a new type of perovskite junctions with polaronic charge carriers. In particular, we studied manganite–titanate p–n heterojunctions made of n-doped SrTi1− yNbyO3, y = 0.002 and p-doped Pr1− xCaxMnO3, x = 0.34 having a strongly correlated electron system. The diffusion length of the polaron carriers was analyzed by electron beam-induced current (EBIC) in a thin cross plane lamella of the junction. In the J–V characteristics, the polaronic nature of the charge carriers is exhibited mainly by the temperature dependence of the microscopic parameters, such as the hopping mobility of the series resistance and a colossal electro-resistance (CER) effect in the parallel resistance. We conclude that a modification of the Shockley equation incorporating voltage-dependent microscopic polaron parameters is required. Specifically, the voltage dependence of the reverse saturation current density is analyzed and interpreted as a voltage-dependent electron–polaron hole–polaron pair generation and separation at the interface.

Low energy scanning transmission electron beam induced current for nanoscale characterization of p–n junctions

“…Hence, the approach of a dead layer successfully describing electron holography data is a too rough approximation for LE‐STEBIC of Si junctions. For PCMO–STNO with a threshold smaller than but still larger than the combined PCMO–STNO diffusion length of , the effect of surface recombination should be less pronounced. For a rough estimate, it can be assumed that surface recombination considerably affects the injection level in the material once the sample thickness is comparable or smaller than the diffusion length which is the case for the Si junction for all thicknesses, whereas for PCMO–STNO the condition is met close to Hence, for the systems studied here we have to conclude that both, dead layers and surface (interface) recombination have to be taken into account in a quantitative model.…”

“…PCMO–STNO p–n heterojunctions have been prepared as described in detail in . Briefly, a 100 nm thick PCMO layer was epitaxially grown by ion beam sputter deposition on an STNO substrate, and sputtered Au and Ti ohmic contacts were used, as illustrated in the inset of Fig.…”

“…in harvesting optical excitations at a broad wavelength range [11][12][13]. Due to the nanosecond charge carrier lifetime in PCMO [14] and the hopping-like small conductivity, the excess carrier diffusion length is in or even below the 10 nm range [13]. Since both materials exhibit similar electron-matter interactionand hence generation volumes -we experimentally realize the limiting cases of D L t and D .…”

“…Since both materials exhibit similar electron-matter interactionand hence generation volumes -we experimentally realize the limiting cases of D L t and D . L t 2 Methods PCMO-STNO p-n heterojunctions have been prepared as described in detail in [13]. Briefly, a 100 nm thick PCMO layer was epitaxially grown by ion beam sputter deposition on an STNO substrate, and sputtered Au and Ti ohmic contacts were used, as illustrated in the inset of Fig.…”

Contribution of Jahn-Teller and charge transfer excitations to the photovoltaic effect of manganite/titanite heterojunctions

“…where J 0 is the temperature-independent prefactor of an Arrhenius-type temperature dependence of J S , which depends on intrinsic material properties. In the case of homojunctions, E B is determined by the band gap; meanwhile, in heterojunctions, E B can be limited by the band offsets [29,32]. V OC should linearly scale with temperature and the logarithm of the short-circuit current density, and the relevant activation barrier can be deduced from the intercept E B = V OC (T → 0).…”