a-Si is commonly considered as a primary candidate for the formation of passivation layer in heterojunction (HIT) solar cells. However, there are some problems when using this material such as significant losses due to recombination and parasitic absorption. To reduce these problems, a wide bandgap material is needed. A wide bandgap has a positive influence on effective transmittance, reduction of the parasitic absorption, and prevention of unnecessary epitaxial growth. In this paper, the adoption of a-SiO_x:H as the intrinsic layer was discussed. To increase lifetime and conductivity, oxygen concentration control is crucial because it is correlated with the thickness, bonding defect, interface density (D_it), and band offset. A thick oxygenrich layer causes the lifetime and the implied open-circuit voltage to drop. Furthermore the thicker the layer gets, the more free hydrogen atoms are etched in thin films, which worsens the passivation quality and the efficiency of solar cells. Previous studies revealed that the lifetime and the implied voltage decreased when the a-SiOx thickness went beyond around 9 nm. In addition to this, oxygen acted as a defect in the intrinsic layer. The D_it increased up to an oxygen rate on the order of 8%. Beyond 8%, the D_it was constant. By controlling the oxygen concentration properly and achieving a thin layer, high-efficiency HIT solar cells can be fabricated.

One-dimensional (1D) photonic crystals (PCs) were prepared by TeOx(2＜x＜3)/SiO2 with thedifference refractive index, and fabricated by sputtering technique from a TeO2 and SiO2 target. TheTeOx(2＜x＜3) layers were fabricated by using the sputtering gas ratio (Ar:O2=40:10). A 10-pair TeOx(2＜x＜3)/SiO2 1D PCs were fabricated with the structure parameters of filling factor=0.5185, and period=410nm. The properties of 1D PCs with and without a defect layer were evaluated by UV-VIS-NIR. Anormal mode 1D PC have a photonic band gap (PBG) in the near infrared (NIR) region from 1,203 to1,421 nm. In the case of 1D PC containing a defect layer, a defect level appears at 1,291 nm. Themeasured transmittance (T) spectra are nearly corresponding to calculated results. After He-Cd laserexposure, the defect level is shifted from 1,291 nm to 1,304 nm.

Mg doped zinc tin oxide (ZTOMg) thin films were prepared on glasses by rf magnetron sputtering. O was introduced into the chamber during the sputtering. The optical properties of the films as a function of oxygen flow rate were studied. The crystal structure, elementary properties, and depth profiles of the films were investigated by X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS), respectively. Bottom-gate trdnsparent thin film transistors were fabricated on N Si wafers, and the variation of mobility, threshold voltage etc. with the oxygen flow rate were observed.

Citations

• A Study on the Chemical Properties of AZO with Crystal Structure and IGZO of Amorphous Structure Due to the Annealing Temperature
  Young Ho So, Jung Ho Song, Dong Myung Seo, Teresa Oh
  Industry Promotion Research.2016; 1(1): 1.     CrossRef