There are many kind of green laser pointer
According to theoretical calculations, I group elements in the formation of ZnO in the primary level by the relatively shallow V elements [49]. Such as Li acceptor level in the valence band at the top of 0.04-0.09 eV, acceptor ionization energy is relatively low. However, due to the ionic radius of Li is very small, easily fit into the space lattice of ZnO, there is as shallow donor Lii. Reported in the literature before were tested Li-doped ZnO n-type semi-insulation or high resistance. Therefore, Li in ZnO the role played by the master or donor controversial. However, the advantages of using PLD and complex high-energy non-equilibrium process, were successfully prepared the Li-doped p-type ZnO thin films [50]. Another video conference of 100mW green laser pointer will be held in next month.
On this basis, the ZnO films were Li-N dual-acceptor co-doping, and further improve the stability of p-ZnO (to stabilize for 15 months), improved the performance of thin-film p-type conductivity, resistivity very low ?( < cm).?1 The film doped with Al composition of n-ZnO homogeneous pn junction showed good rectifying behavior [51]. ZnO DC Look, senior international experts, Professor spoke highly of the work, that this is "the most encouraging results". But the Li-N dual-acceptor co-doping mechanism needs further study [54]. Of Li-doped p-type Zn1-xMgxO alloy films grown by PLD have also been explored to study the deposition parameters such as substrate temperature, oxygen pressure, Mg content, etc. on the p-Zn1-xMgxO: Li film structure, electrical, optical properties [52, 53]. The customer and manufacturer have achieved the agreement on the wholesale price of green laser pointer .
Recently, the use of PLD method to achieve a stable Na-doped p-type ZnO thin films, and observed p-ZnO: Na / n-ZnO: Al homogeneous pn junction at 160K electroluminescent [55]. In addition to Ag as the acceptor dopant, in the Al2O3 (0001) also gained on the substrate p-type ZnO (p-ZnO: Ag) film [56]. Study found that changes in p-type conductivity has a window, only in the 200-250 ℃ temperature range of this small place. Proved, I group elements, the smaller atomic radius, level shallow acceptor dopant ZnO is an ideal choice. ZnSe is a direct wide bandgap II-VI semiconductor material, the band gap of 2.67eV (464nm), is the preparation of the blue - green light-emitting device of the candidate materials. All the technical personnel are required to take part in the design liaison meeting of 50mW blue violet laser pointer .
While its characteristic absorption peak of the strongest in the solar spectrum region, is an ideal solar cell material. ZnSe can replace the CdS buffer layer for solar cells, so that the preparation of Cd-free solar cells more economical and more environmentally friendly. Preparation of ZnSe thin film technologies are MOCVD, MBE, PLD, evaporation, and so on. This chapter deals with PLD technology, simple examples in ZnSe films grown on GaAs substrates, with lattice mismatch of GaAs is about 0.27%. Fudan University, Xu Ning et al [57] with 248nm KrF excimer pulsed laser ablation of ZnSe deposition of ZnSe thin film target. Target the use of polycrystalline ZnSe films, the substrate with polished GaAs (100). Atomic force microscopy (AFM) observation showed that the GaAs (100) ZnSe thin films deposited an average roughness of 3-4nm. X-ray diffraction (XRD) results show that the ZnSe film (400) peak width at half height (FWHM) of 0.4-0.5 °. The customer would like to increase the purchase quantity of 200mW green Laser Pointer .
India T. Ganguli et al [58] using off-axis PLD technology in GaAs (100) substrates to be quasi-strain ZnSe epitaxial films, test analysis found that the crystallization of thin films of good quality than ordinary PLD, which was mainly due to the growth axis when burning loss of lower energy particles reason. Poland A. Bylica et al [59] on ITO substrate PLD growth CdTe, CdS and CdTe / CdS multi-layer structure, using a YAG: Nd3 + laser, wavelength 1046nm, pulse width 40ns, energy 400mJ. Target for the CdTe, CdS crystal, target and substrate spacing 30mm, substrate temperature 470K. The growth of CdTe thin film of porous structure, between the columnar grains do not touch, the film has good optical absorption properties. Not been annealed CdTe / CdS multilayer structures exhibit typical IV characteristics of the photodiode, that based on this structure CdTe / CdS junction photovoltaic devices without annealing, the production cycle can be shortened and reduced production costs. The director is carefully arranging the production preparation of green laser pointer .
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