The reasons for low output power of AlGaInP Light Emitting Diodes (LEDs) have been analysed. LEDs with AlGaInP material have high internal but low external quantum efficiency and much heat generated inside especially at a large injected current which would reduce both the internal and external quantum efficiencies. Two kinds of LEDs with the same active region but different window layers have been fabricated. The new window layer composed of textured 0.5 μm GaP and thin Indium-Tin-Oxide film has shown that low external quantum efficiency (EQE) has serious impaction on the internal quantum efficiency (IQE), because the carrier distribution will change with the body temperature increasing due to the heat inside, and the test results have shown the evidence of LEDs with lower output power and bigger wavelength red shift.

The (Al0.1Ga0.9)0.5In0.5P, four-element alloy, whose band is direct, is used to make optoelectronic devices. The wavelength of the material is about 630nm. When it is epitaxially grown by low press-metalorganic chemical vapor deposition(LP-MOCVD), its quality will depend on temperature, one of the most important conditions. So it is essential to find out the best temperature of growth. The quantum wells of the (Al0.1Ga0.9)0.5In0.5P are grown at 700 ℃, 680 ℃, 670 ℃ and 660 ℃ respectively. The best temperature, which is found out by the results of photoluminescence PL, is about 670 ℃. The reasons are given by the results of PL, surfaces of wafers and the flow field simulation of MOCVD. The revaporization of In at high temperature and the incorporation of O at low temperature can lead to bad quality. An available path to solve growth at high temperature is to increase the effective density of In.

The MetroIn_DPM digital near-view industrial photogrammetry system and the simulation experiment of Axyz/MTM theodolite industrial measurement system were carried out in the laboratory to demonstrate the feasibility of the MetroIn_DPM system applied to the project. In addition, MetroIn_DPM digital close-range industrial photoelectric measurement system was used to monitor the gas station tent and column, and the deformation and trend of the gas station tent were obtained.