InN materials have very important application value in the field of optoelectronics. InN is a semiconductor material with excellent performance. InN's forbidden band width may be around 0.7 eV instead of the previously accepted 1.9 eV, so a continuously adjustable direct bandgap from 0.6 eV (InN) to 6.2 eV (AlN) can be obtained by adjusting the alloy composition. A single system of materials can be fabricated to cover photovoltaic elements from the near infrared to deep ultraviolet spectral range. Therefore, InN is expected to become an excellent semiconductor material for long-wavelength semiconductor optoelectronic devices, full-color displays, and high-efficiency solar cells. First, the current problems in the manufacture of InN film Preparation of high quality InN bulk single crystal materials and epitaxial thin film single crystal materials is the premise for the research and development of InN materials. However, there are two major difficulties in manufacturing InN films. First, the dissociation temperature of InN material is low, and it decomposes at about 600 °C, which requires InN under low temperature growth, and the decomposition temperature of NH3 as a nitrogen source is higher, requiring about 1000 °C, which is a growth of InN. For contradictions, it is difficult to prepare single crystal materials by a general method. Currently, the most common methods for manufacturing InN thin films are MBE, HVPE, magnetron sputtering, and MOCVD. Second, it is difficult to find a suitable substrate. Since the InN single crystal is very difficult to obtain, it is necessary to obtain a heteroepitaxial InN film, which makes it difficult to avoid the large problem of lattice matching. Generally, the buffer layer of the long nitride on the sapphire substrate, and then the heteroepitaxial InN film, research shows that the InN film grown on the GaN buffer layer is ideal. MBE technology growth can precisely control the thickness of the wafer film, and obtain excellent wafer material, but the growth rate is slower. It takes too long for the thicker wafer growth to meet the requirements of large-scale production. For optoelectronic devices, especially LED and LD wafers, MOCVD technology is generally used. This is because the MOCVD technology uses the In organic source as the metal source, N2 as the carrier gas, and NH3 as the nitrogen source, and the InN growth is performed at a low temperature of about 500 ° C by a two-step process or other means. The growth rate of MOCVD is moderate, and the thickness of the epitaxial film can be controlled relatively accurately, and is particularly suitable for large-scale industrial production of photovoltaic devices. Second, the electrical properties of InN materials The most concern about InN materials is the bandgap problem, and many questions remain unresolved until now. Although many people now think that the band gap is 0.6-0.9eV, some people think that the band gap of InN may be slightly larger than this value: 1.25–1.30 eV. These samples with a band gap of 0.6-0.7 eV may hold deep defect levels with a larger band gap. It is considered that there is a deep level defect in InN, which is about 0.5 eV, so that 0.7eV corresponds exactly 1.25-1.30eV. Samples with a low bandgap that are considered to have a higher bandgap are due to impurities, Moss-Burstein effect, or other factors. The effect of oxygen doping on the band gap of InN is obtained by incorporation of different oxygen impurities, and the band gap is continuously changed from 0.7-2.0, indicating that oxygen is a factor that causes the band gap to broaden. Another important issue with InN materials is that InN exhibits a strong n-type conductance characteristic, which is somewhat similar to GaN, but this problem is more serious in InN. In Fer's Fermi stable level EB is in the conduction band, which means that even if the electron concentration increases in InN, the Fermi level increases, and it is difficult to form a p-type intrinsic compensation defect, which makes the electron saturation. The concentration becomes very large, and theoretical calculations show that the saturated electron concentration NS is close to 1021 cm-3. (Editor: Wen Jing) Fishing Light,LED Flashlight,Rechargeable Flashlight Hi-Max Technology Co., Ltd. , http://www.gdflashlight.com