Photocarrier Injection and Current-Voltage Characteristics of a La0.8Sr0.2MnO3/SrTiO3:Nb Heterojunction at Low Temperature

TL;DR

This study demonstrates a La0.8Sr0.2MnO3/SrTiO3:Nb heterojunction functioning as an efficient UV photodiode at low temperatures, with notable photocarrier injection and photovoltaic properties.

Contribution

It reports the fabrication and characterization of a novel heterojunction that exhibits efficient UV detection and hole doping via photocarrier injection at low temperatures.

Findings

Large external quantum efficiency of 28% as a UV photodiode.

Photocarrier injection increases surface hole density to 3.0 x 10^13 cm^-2.

Heterojunction operates effectively down to 10 K.

Abstract

An epitaxial heterojunction made of a p-type perovskite manganite La0.8Sr0.2MnO3 film and an n-type strontium titanate SrTiO3:Nb substrate has been fabricated by the pulsed laser deposition technique. The I - V characteristics and photovoltaic properties are measured under a UV light irradiation in a wide temperature range down to 10 K. It is found that the junction works as an efficient UV photodiode with a large external quantum efficiency of 28%. It is also demonstrated that the manganite film can be doped with a certain amount of holes by the photcarrier injection. The maximum surface hole density is estimated to b 3.0 X 10^13 cm^-2.