Optical And Electronic Properties Studies In InGaN/GaN Film Grown By MOCVD

From the beginning of1990s,the reaserch of high-brightness LED is developing rapidly.Since high-brightness LED adopts double hetero-structure,it demands that the material should have good lattice match.This need put a strict limit on the material system which is used for the hetero-junction LED.The III-V nitride semiconductor materials have excellent photoelectric perfomance and stable chemical properties,they can work under those conditions such as hight temperature,acid,alkali and radicalization,moreover,they have wide band-gap range.As a result,they have considerable affinity in the area of high—Power eleetric apparatus and have already attracted lots of researchers both internal and overseas.The III-V nitrides which interest people most are AIN, GaN, InN and their alloys.By controlling their respective component, their band gap can continuous change from0.7eV of InN to3.4eV of GaN until6.2eV of AIN, which cover the entire visible light district and expand to the scope of the UV, consequently are fit for making high—brightness LED.This paper focusing on the photoelectric properties of Ⅲ-Nitrides and combing with SEM and AFM test method to launch the research and exploration, mainly test the photoelectric properties of InGaN/GaN single quantum under different growth conditions. The main conclusions are as follows:1. Let the other conditions remain the same and only change its growth temperature. When the growth temperature is about780℃to830℃, the appearances of InGaN samples are great difference. The higher the temperature, the smoother the material will be. But the content of indium reduced. In addition, it gives rise to an indium enrichment phenomenon.2. The room temperature photoluminescence spectrum display luminescence wavelength of samples blueshift along with the increase of growth temperature. V type pit can greatly influence the luminous efficiency. It shares the consistent rules with the density of V type pit. The luminous efficiency in the vicinity of V shaped pits samples is obviously higher than that without pit area. Bound excition’s luminescent mechanism is comparatively obvious.3. Through the measurement of Temperature-dependent Photoluminescence from15K to300K of a sample, Energy band presents an S curve along with the environmental temperature rising, which can be explained with localized exciton recombination luminescence of the class of quantum dots produced by In component fluctuation and Energy band contraction effect.4. With the growth temperature of Film increased, the content of In decreased, the content of Ga and the quality of effective electron increased, alloy scattering effect is strengthened, and carrier mobility decline. Along with the growth temperature is further increased, the film surface becomes smooth, its impurities and defects decrease rapidly, thus influences of the impurity scattering and defect scattering is weakened, causing the electronic moblity rising rapidly again. After the samples annealing, the carrier concentration decreases, which make Holzer moblity improve.