Co-reporter:Chen Ge, Kui-juan Jin, Hui-bin Lu, Cong Wang, Guang-ming Zhao, Li-li Zhang, Guo-zhen Yang
Solid State Communications 2010 Volume 150(43–44) pp:2114-2117
Publication Date(Web):November 2010
DOI:10.1016/j.ssc.2010.09.016
The mechanisms for the greatly enhanced lateral photovoltaic effect in the perovskite oxide heterostructures are studied by solving time-dependent two-dimensional drift-diffusion equations self-consistently. By our calculations, we find that the lateral photovoltage of pp-type material is larger than that of nn-type material owing to the larger drift electric field induced in the pp-type material than that in the nn-type material. Moreover, the built-in electric field at the interface between the thin film and substrate can also enhance the lateral photovoltage. The above two mechanisms can well explain one-order-of-magnitude enhancement of the lateral photovoltaic effect in the perovskite heterostructures. In addition, we find that the materials with larger mobility ratio have a stronger Dember effect. Such an understanding of the mechanisms for the enhancement of lateral photovoltage in oxide heterostructures should be useful in further designing of the structures of position-sensitive detectors and new THz sources.
Co-reporter:Kui-juan Jin;Hui-bin Lu;Kun Zhao;Chen Ge;Meng He ;Guo-zhen Yang
Advanced Materials 2009 Volume 21( Issue 45) pp:4636-4640
Publication Date(Web):
DOI:10.1002/adma.200901046
Abstract
Multilayer structures have emerged as a leading research topic and researchers expect that multilayers may lead to interesting artificial materials with novel properties. In this Research News we show that the introduction of interfaces into perovskite oxides can induce a series of novel properties including an unusual positive magnetoresistance, great enhancement of lateral photovoltage in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3, and an electrical modulation of the magnetoresistance in multi-p-n heterostructures of SrTiO3−δ/La0.9Sr0.1MnO3/SrTiO3−δ/La0.9Sr0.1MnO3/Si. This novel positive magnetoresistance is attributed to the creation of a space charge region at the interface where the spin of the carriers is anti-parallel to that of the carriers in the region far from the interface of manganese oxide in the heterostructures.
Co-reporter:Chun-lian Hu, Kui-juan Jin, Peng Han, Hui-bin Lu, Leng Liao, Guo-zhen Yang
Solid State Communications 2009 Volume 149(7–8) pp:334-336
Publication Date(Web):February 2009
DOI:10.1016/j.ssc.2008.11.029
Taking spin current into account, the dependence of magnetoresistance with negative bias and that with doping concentration with various spin polarization in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3p–np–n junction are obtained theoretically. The variation of the magnetoresistance value with the reverse bias is found to be due to the competition between the tunneling rate of electrons in eg1↑ band at the homogeneous region of La0.9Sr0.1MnO3to t2g↓t2g↓ band and that to eg2↑ band at the interface region of La0.9Sr0.1MnO3. From the comparison of calculated magnetoresistance and the experimental data, a dependence of spin polarization of the system on the applied magnetic field is obtained.
Co-reporter:Leng Liao, Kui-juan Jin, Hui-bin Lu, Peng Han, Meng He, Guo-zhen Yang
Solid State Communications 2009 Volume 149(23–24) pp:915-918
Publication Date(Web):June 2009
DOI:10.1016/j.ssc.2009.03.029
The dynamic process of photoelectric effects in the La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 heterostructure is theoretically revealed by solving equations consisting of time dependent drift–diffusion, Richardson thermionic emission current, and Shockley–Read–Hall recombination. The calculated time dependent evolution of photovoltage and the variation of carrier concentration are obtained. Present results indicate that a smaller parallel resistance should result in faster photoelectric response, but reduce the peak value of the photovoltage in a La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 heterojunction. In addition, the increase of the carrier mobilities induced by applying higher energy photons can decrease the rise time but increase the peak value of the photovoltage.
Co-reporter:Leng Liao, Kui-juan Jin, Hui-bin Lu, Peng Han, Meng He, Guo-zhen Yang
Solid State Communications (June 2009) Volume 149(23–24) pp:915-918
Publication Date(Web):1 June 2009
DOI:10.1016/j.ssc.2009.03.029
The dynamic process of photoelectric effects in the La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 heterostructure is theoretically revealed by solving equations consisting of time dependent drift–diffusion, Richardson thermionic emission current, and Shockley–Read–Hall recombination. The calculated time dependent evolution of photovoltage and the variation of carrier concentration are obtained. Present results indicate that a smaller parallel resistance should result in faster photoelectric response, but reduce the peak value of the photovoltage in a La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 heterojunction. In addition, the increase of the carrier mobilities induced by applying higher energy photons can decrease the rise time but increase the peak value of the photovoltage.
Co-reporter:Chun-lian Hu, Kui-juan Jin, Peng Han, Hui-bin Lu, Leng Liao, Guo-zhen Yang
Solid State Communications (February 2009) Volume 149(7–8) pp:334-336
Publication Date(Web):1 February 2009
DOI:10.1016/j.ssc.2008.11.029
Taking spin current into account, the dependence of magnetoresistance with negative bias and that with doping concentration with various spin polarization in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3p–n junction are obtained theoretically. The variation of the magnetoresistance value with the reverse bias is found to be due to the competition between the tunneling rate of electrons in eg1↑ band at the homogeneous region of La0.9Sr0.1MnO3to t2g↓ band and that to eg2↑ band at the interface region of La0.9Sr0.1MnO3. From the comparison of calculated magnetoresistance and the experimental data, a dependence of spin polarization of the system on the applied magnetic field is obtained.
