Epitaxial films of an oxide-diluted magnetic semiconductor with rutile structure, Mn-doped SnO2, have been fabricated by pulsed-laser deposition. As the Mn content increases, systematic changes in lattice constants and in-gap absorption are observed. Magnetization measurements show almost paramagnetic behavior. The injection of n-type carrier over 1020 cm−3 is achieved by Sb doping. A Sn0.95Mn0.05O2:Sb film shows giant positive magnetoresistance as large as 60% at 5 K.

Rutile-type oxide-diluted magnetic semiconductor: Mn-doped SnO2

Highly transparent and conductive zinc-stannate thin films, ZnSnO3, have been prepared by rf magnetron sputtering using a target composed of ZnO–SnO2 ( SnO2, 78 wt%). A resistivity as low as 4×10-3 Ωcm and an average transmittance above 80% in the visible range were obtained for undoped zinc-stannate films deposited with substrate temperatures ranging from room temperature to 300°C. The zinc-stannate films were relatively more stable in an oxidizing environment at high temperatures than either ZnO or SnO2 films. In addition, thermal stability in a hydrogen environment was improved over SnO2 films, and chemical stability in both acidic and basic solutions was improved over ZnO films.

https://iopscience.iop.org/article/10.1143/JJAP.33.L1693/pdf

Highly Transparent and Conductive Zinc-Stannate Thin Films Prepared by RF Magnetron Sputtering

Highly conductive and transparent films of Si-doped ZnO have been prepared by rf magnetron sputtering of a ZnO target with SiO2 or SiO dopant added. Films with resistivity as low as 3.8×10-4 Ω cm and average transmittance above 85% in the visible region can be produced on low temperture substrates at below 250°C. Great improvement in the stability of the resistivity for use at high temperatures was obtained for Si-doped ZnO films in comparison with undoped films.

https://iopscience.iop.org/article/10.1143/JJAP.25.L776/pdf

Highly Conductive and Transparent Silicon Doped Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering

Textured ZnO films have been grown by metalorganic chemical vapor deposition (MOCVD) using diethylzinc (DEZ) and H2O as reactant gases. It was found that the surface morphology of films was strongly dependent on the substrate temperature. For the low substrate temperature of 150°C, the surface consists of uniformly sized tetrapodlike features. These undoped films have a high transparency in a wide wavelength range from 400 nm to 1400 nm. The low-resistivity ZnO films have also been succesfully grown using a dopant gas of B2H6 diluted with H2. A sheet resistivity as low as 10 Ω/ was obtained.

Textured ZnO Thin Films for Solar Cells Grown by Metalorganic Chemical Vapor Deposition

We successfully increased the haze value of zinc oxide (ZnO) films fabricated using metal–organic chemical vapor deposition (MOCVD) by conducting glass-substrate etching before film deposition. It was found that with increasing the glass treatment time, the surface morphology of ZnO films changed from conventional pyramid-like single texture to greater cauliflower-like multi texture. Further, the rms roughness and the haze value of the films increased remarkably. Using ZnO films with a high haze value as front transparent conductive oxide (TCO) films in hydrogenated microcrystalline silicon (µc-Si:H) solar cells, we improved the quantum efficiency of these cells particularly in the long-wavelength region.

https://iopscience.iop.org/article/10.1143/APEX.3.051102/pdf

ZnO Films with Very High Haze Value for Use as Front Transparent Conductive Oxide Films in Thin-Film Silicon Solar Cells

The relationship between average grain size on the surface of SnO 2 transparent conductive film and conversion efficiency of the a-Si:H solar cell was investigated. a-Si:H solar cells were fabricated on SnO 2 /glass substrates with various grain sizes. The cell structure was glass/p(SiC)-i-n/Al and the effective cell area was 4 × 10-2cm2. The reflectivity from the glass substrate was reduced to about 7 percent with increasing the grain size from 0.1 to 0.8µm, and the short-circuit current was inceased from 12 to 14mA/cm2. A 7.9 percent of conversion efficiency was achieved using milky SnO 2 film of 0.4-µm average grain size at AM-100mW/cm2.

Efficiency of the a-Si:H solar cell and grain size of SnO 2 transparent conductive film

Dependence of conversion efficiency of a-Si:H p-i-n solar cells on the material of transparent conductive film substrates was studied. Irrespective of preparation method of the transparent conductive film, SnO 2 films gave an advantage over ITO films for high efficiency cell production by a parallel plate electrode type plasma C.V.D. equipment. A conversion efficiency of 7.19% was achieved by optimizing preparation conditions of the SnO 2 film and the a-Si:H film.

N. Shiba

Papers

Efficiency of the a-Si:H solar cell and grain size of SnO 2 transparent conductive film

High efficiency a-Si:H p-i-n solar cell using a SnO 2 /glass substrate