Electrical and Optical Properties of GaSe Thin Films

The structure, electrical transport, and optical properties of GaSe films fabricated by means of radio-frequency (RF) magnetron sputtering in Ar were investigated. The as-sputtered GaSe films were amorphous, and their optical energy gap Eg are 1.9～2.6 eV. The effect of the synthesis conditions on the optical and electrical properties of the GaSe films has also been studied

Effect of compensation doping on the electrical and optical properties of mid-infrared type-II InAs/GaSb superlattice photodetectors

This paper presents a theoretical study on the electrical and optical properties of mid-infrared type-II InAs/GaSb superlattices with different beryllium concentrations in the InAs layer of the active region. Dark current, resistancearea product, absorption coefficient and quantum efficiency characteristics are thoroughly examined. The superlattice is residually n-type and it becomes slightly p-type by varying beryllium-doping concentrations, which improves its electrical performances. The optical performances remain almost unaffected with relatively low p-doping levels and begin to deteriorate with increasing p-doping density. To make a compromise between the electrical and optical performances, the photodetector with a doping concentration of 3 ×10^15 cm-3 in the active region is believed to have the best overall performances.

Electrical and optical properties of Sb-doped ZnO thin films synthesized by sol–gel method

Sb-doped ZnO thin films with different values of Sb content （from 0 to 1.1 at.%） are deposited by the sol-gel dip- coating method under different sol concentrations. The effects of Sb-doping content, sol concentration, and annealing ambient on the structural, optical, and electrical properties of ZnO films are investigated. The results of the X-ray diffraction and ultraviolet-visible spectroscopy （UV-VIS） spectrophotometer indicate that each of all the films retains the wurtzite ZnO structure and possesses a preferred orientation along the c axis, with high transmittance （〉 90%） in the visible range. The Hall effect measurements show that the vacuum annealed thin films synthesized in the sol concentration of 0.75 mol/L each have an adjustable n-type electrical conductivity by varying Sb-doping density, and the photoluminescence （PL） spectra revealed that the defect emission （around 450 nm） is predominant. However, the thin films prepared by the sol with a concentration of 0.25 mol/L, despite their poor conductivity, have priority in ultraviolet emission, and the PL peak position shows first a blue-shift and then a red-shift with the increase of the Sb doping content.

Effect of the Sputtering Parameters on the Structure and Properties of Cu_3N Thin Film Materials

Copper nitride （Cu3N） thin films were successfully deposited on glass substrates by reactive radio frequency magnetron sputtering.The effects of sputtering parameters on the structure and properties of the films were studied.The experimental results show that with increasing of RF power and nitrogen partial pressure,the preferential crystalline orientation of Cu3N film is changed from （111） to （100）.With increasing of substrate temperature from 70 ℃ to 200 ℃,the film phase is changed from Cu3N phase to Cu.With increasing sputtering power from 80 W to 120 W,the optical energy decreases from 1.85 eV to 1.41 eV while the electrical resistivity increases from 1.45 ×102 Ω·cm to 2.99×103 Ω·cm,respectively.

Effect of Oxygen Partial Pressure on Epitaxial Growth and Properties of Laser-Ablated AZO Thin Films

Al-doped ZnO（AZO） thin films were grown on c-sapphire substrates by laser ablation under different oxygen partial pressures（P_（O2））.The effect of P_（O2） on the crystal structure,preferred orientation as well as the electrical and optical properties of the films was investigated.The structure characterizations indicated that the as-grown films were single-phased with a wurtzite ZnO structure,showing a significant c-axis orientation.The films were well crystallized and exhibited better crystallinity and denser texture when deposited at higher P_（O2）.At the optimum oxygen partial pressures of 10- 15 Pa,the AZO thin films were epitaxially grown on c-sapphire substrates with the（0001） plane parallel to the substrate surface,i e,the epitaxial relationship was AZO（000 1） // A1_2O_3（000 1）.With increasing P_（O2）,the value of Hall carrier mobility was increased remarkably while that of carrier concentration was decreased slightly,which led to an enhancement in electrical conductivity of the AZO thin films.All the films were highly transparent with an optical transmittance higher than 85%.

Influence of Substrate Temperature and Nitrogen Gas on Zinc Nitride Thin Films Prepared by RF Reactive Sputtering

Zinc nitride （Zn3N2） thin films were prepared by radio frequency （RF） magnetron sputtering on quartz glass at different substrate temperatures.The structure and composition were characterized by X-ray diffraction and Raman-scattering measurements,respectively.The polycrystalline phase Zn3N2 films appeared when the ratio of the N2 partial pressure to the total pressure reached 1/2.The effects of the substrate temperature on the electrical and optical properties of the Zn3N2 films were investigated by Hall measurements and optical transmission spectra.The electrical and optical properties of the films were highly dependent on the substrate temperature.With the substrate temperature increasing from 100 to 300℃,the resistivity of the Zn3N2 films decreased from 0.49 to 0.023Ω·cm,the carrier concentration increased from 2.7×10^16 to 8.2×10^19cm^-3,and the electron mobility decreased from 115 to 32cm^2/（V·s）.The deposited Zn3N2 films were considered to be n-type semiconductors with a direct optical band gap,which was around 1.23eV when the substrate temperature was 200℃.

Characterization of ZnO:Al Films Deposited on Organic Substrate by r.f. Magnetron Sputtering

Transparent conducting Al-doped zinc oxide (ZnO:AI) films with good adhesion have been deposited on polyimide thin film substrates by r.f. magnetron sputtering technique at low substrate temperature (25-180℃). The structural, optical and electrical properties of the deposited films were investigated. High quality films with electrical resistivity as low as 8.5×10-4 Ω·cm and the average transmittance over 74% in the wavelength range of the visible spectrum have been obtained. The electron carrier concentrations are in the range from 2.9×1020 to 7.1×1020 cm-3 with mobilities from 4 to 8.8 cm2 V-1s-1. The densities of the films are in the range from 4.58 to 5.16 g/cm-3.

High conductive and transparent AI doped ZnO films for a-SiGe：H thin film solar cells

Al doped zinc oxide （AZO） films were prepared by mid-frequency magnetron sputtering for silicon （Si） thin film solar cells. Then, the influence of deposition parameters on the electrical and optical properties of the films was studied. Results showed that high conductive and high transparent AZO thin films were achieved with a minimum resistivity of 2.45 × 10^-4 Ω·cm and optical transmission greater than 85% in visible spectrum region as the films were deposited at a substrate temperature of 225℃ and a low sputtering power of 160 W. The optimized films were applied as back reflectors in a-SiGe：H solar cells. A relative increase of 19% in the solar cell efficiency was achieved in comparison to the cell without the ZnO films doped with Al （ZnO：Al）.

Preparation of SnS∶Ag Thin Films by Pulse Electrodeposition

SnS：Ag thin films were deposited on ITO by pulse electro-deposition. They were characterized with X-ray diffraction spectroscopy and atomic force microscope. The as-deposited films have a new phase （Ag8SnS6） with good crystallization and big grain size. The conductivity of the films was measured by photoelectrochemical test. It is proved that the SnS：Ag films are p-type of semiconductor. Hall measurement shows that the carrier concentration of the films increases, while their resistivity decreases after Ag-doping.

Effect of Cr/In-doping on the crystalline quality of bulk ZnTe crystals grown from Te solution by temperature gradient solution growth(TGSG) method

The properties of undoped, Cr-doped, and In-doped bulk ZnTe crystals grown by the TGSG method were compared. Cr/In-doping leads to a slight red-shift of the absorption edge. Cr-doping also creates two characteristic absorption bands, centered at about 1750 nm and beneath the fundamental absorption edge. However, the fundamental reflectance spectra are not sensitive to the dopants. The resistivity of undoped, Cr-doped, and In-doped ZnTe is about 102 Ω.cm, 10^3 Ω.cm, and 10^8 Ω-cm, respectively. Only In-doped ZnTe has an IR transmittance higher than 60% in the range of 500 to 4000 cm-1. However, the IR transmittance of Cr-doped ZnTe is very low and decreases greatly as the wavenumber increases, which is mainly attributed to the scattering effects caused by some defects generated by Cr-doping.