Advantages And Disadvantages Of Zinc Oxide

Semiconductor Nano crystals or quantum dots are materials that are typically 2-20 nm in diameter, consisting of approximately twelve to fourteen thousand atoms. The effect of quantum confinement results, in the electrons and holes in the Nano crystal to exhibit quantized energy states; thus enabling them to exhibit novel physical properties that are not found in their bulk counterparts. Research in semiconductor quantum dots started with the realization that the optical and electronic properties of these particles were strongly dependent on particle size, due to quantum confinement of the charge carriers in small spaces.

Zinc got it’s name from a German word “Zink”. Zink has very helpful uses. Zinc is used to make white blood cells in your body also used to make other metals such as Brass and

Compared to TiO2, Figure 26a and 26b, which represent the XRD for titania film, it is observed that the crystallinity increases with temperature, which is the same behavior as with zinc oxide films. Furthermore, there is great difference between the samples with SiO2 layer and those without barrier layer. In the samples without barrier layer, sodium diffusion inhibit crystals growing in the film [7].

By sеvеral diffеrеnt mеthods, including mеtal-organic vapour phasе еpitaxy (MOVPЕ), molеcular bеam еpitaxy (MBЕ) and pulsеd lasеr dеposition (PLD), thе ZnO еpitaxial layеrs and quantum wеlls havе bееn grown. Thе growth in c-axis oriеntеd dеspitе growth on a rangе of singlе crystal substratеs, including ZnO, sapphirе and Si oriеntеd along various crystal

It demonstrated that Na doping had a widen effect for the band gap of CuO, which was the first report here. Interestingly, the band gap shifts from 1.49eV to 1.46eV with the increase in Na doping from 0.0 to 3.0%, with was due to the band gap tailoring effect. The Na content was further increased when the secondary phase formed and the band gap shift to the higher energy 1.51eV, 1.53eV for 5.0% and 7.0% Na-doped CuO nanostructures. In contrast, the formation of the Na2O secondary phase caused an enhancement of the Eg value. Hence, to summarize the Eg value of the Na doped CuO nanoparticles depends upon a variety of parameters such as the size and presence of the Na dopant in different forms. These unique characteristics were influenced by the quality and physical properties of the Na-doped CuO nanoparticles and these were strongly related to the preparation method.

Now a days, Nanotechnology is widely used in many industrial areas such as, computing, pharmaceuticals, cosmetics, textile industries and many more. The major challenge is not only to make these materials smaller in size in order to store or process more information but also to optimize the synthesis process. However, the additional key point of the nanotechnology revolution within the next decades is that it will have the capability to use the advantage of mesoscopic properties of such Nano sized materials. These properties can strongly differ from the respective bulk counterparts due to quantum confinement or the high surface-to-volume ratio. For example, there will be increase in bandgap of these Nano materials for which it can be used

The efficiency of perovskite solar cells has increased rapidly in the past decade (3.8% in 2009 to 22.1% in 2016), and the speed of this progress in perovskite photovoltaics makes it an attentive focus on solar energy. In 20 years, our team has a vision that perovskite solar cells will be able to have an energy efficiency of at least 50% (based off how fast the efficiency has grown just in the last decade). There are limitations in perovskites today, but as time passes on, it is increasingly possible to break through those limitations and enable perovskites to have a higher energy efficiency.

They have good mechanical strength, and are hard, chemically inert and immune to humidity, which lead to the application of piezoelectric ceramics for the generation of voltage, electromechanical actuation, frequency control and the generation and detection of acoustic and ultrasonic energy [1, 3]. Piezoelectric ceramics are used in generators, sensors, actuators, and transducers, etc. [4]. They are also used in daily life such as some piezoelectric cigarette lighters, most battery operated smoke detector alarms, many gas grill igniters [5]. There have been a variety of research due to the wide applications of piezoelectric ceramics and the prospect for future development and improvement. Therefore, this paper will briefly introduce the history, applications and future development of piezoelectric ceramic

The influence of gamma irradiation on the electrical and dielectric properties of AgNO3/ PVA films was investigated. The films were prepared by in-situ chemical reduction techniques, then irradiated with different gamma doses (25, 50, 75, 100, 125 KGy). The content of the Ag in the PVA film were determined by using atomic absorption spectroscopy (AA), and were found to be 0.4 wt %. The films have been characterized through dielectric spectroscopy and I–V measurements. As a result, the dielectric constant (ε) value decreases as the gamma irradiation doses increase. The conductivity of the films and dielectric loss (tan δ) of increases with increasing the gamma irradiation doses. The conductivity was found (σ = 4.9 x10−8 S m−1) for 125 KGy. Frank-poole emission is the prevailing transport mechanism for all samples.

The influence of gamma irradiation on the electrical and dielectric properties of AgNO3/ PVA films was investigated. The films were prepared by casting techniques, then irradiated with different gamma doses (25, 50, 75, 100, 125 KGy). The content of the Ag in the PVA film were determined by using atomic absorption spectroscopy (AA), and were found to be 0.4 wt %. The films have been characterized through dielectric spectroscopy and I–V measurements. As a result, the dielectric constant (ε) value decreases as the gamma irradiation doses increase. The conductivity of the films and dielectric loss (tan δ) of increases with increasing the gamma irradiation doses. The conductivity was found (σ = 4.9 x10−8 S m−1) for 125 KGy. Frank-poole emission is the prevailing transport mechanism for all samples.

The doping of semiconductor by rare earth metal nanoparticles is an effective way for increasing in photocatalytic activity. Zinc oxide and Lanthanum doped Zinc oxide nanoparticles were synthesized by modifying the gel-combustion method. It was found that La can greatly enhance the cytotoxicity and photocatalytic activity of ZnO nanoparticles towards various cell lines and paracetamol drug. These nanoparticles were characterized by various spectroscopic and other techniques which clearly revealed the presence of lanthanum ions. The UV-vis spectroscopy displayed the absorption edge shifts towards the visible region after doping with La which is extremely favorable for absorbing the visible light. We compared the enhancing effect of La ions and found that La doped ZnO nanoparticles is more effective than ZnO nanoparticles in promoting the generation of hydroxyl radicals, holes and the photocatalytic activity of

substrate layer on glass substrate and photonic crystals. Micro-lens arrays (MLAs) or mesh pattern have also been tested by the researchers. Due to the addition of cylindrical MLAs on substrate surface, the external quantum efficiency of the OLEDs has increased to ~ 45%. Nano-scale Si3N4 layer has also been investigated on the substrate layer of OLEDs to increase the external quantum efficiency up to 50%. Although the external quantum efficiency has increased significantly because of the addition of micro/nano-structures in OLEDs, still there is scope the external quantum efficiency of the OLEDs.

These factors can be eliminated by substitutional doping-based photochemical methodology to achieve the simultaneous reduction and doping through ultraviolet laser irradiation in the presence of a dopant precursor gas [1]. This will not lead to any structural disorder, hence, no effects on the sheet resistance and optical characteristics by the defects invasion. These doping and reduction level of graphene could be controlled by varying the irradiation time.

Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor with a bandgap of 3.4 eV commonly used in light-emitting diodes since the 1990s. GaN has a low sensitivity to ionizing radiation which makes it a suitable material for solar panels on satellites. Various military and space application also benefit from the usage if this radiation hardened material. Besides the wide bandgap, high breakdown field and high saturation velocity of GaN make it very promising for high power, high-speed and high temperature electronic devices. GaN devices offer five key characteristics: high dielectric strength, high operating temperature, high current density, high speed switching and low on-resistance. These characteristics are due to the properties of GaN, which, compared to silicon, offers ten times higher electrical breakdown characteristics, three times the bandgap, and exceptional carrier mobility. Low resistance Ohmic contacts with a smooth morphology, and good edge acuity and thermal stability are imperative in the successful implementation of all these devices, particularly high power devices which require high power conversion efficiency and heat management. The

We have now discussed the two extremes in electronic materials; a conductor, and an insulator we will now move to a material that lies in between these two, a semiconductor. The