Mg-doped p-InGaN layers with In composition of about 10% are grown by metalorganic chemical vapor deposition (MOCVD).The effect of the annealing temperature on the p-type behavior of Mg-doped InGaN is studied.It is found that the hole concentration in p-InGaN increases with a rising annealing temperature in the range of 600-850°C, while the hole mobility remains nearly unchanged until the annealing temperature increases up to 750°C,after which it decreases.On the basis of conductive p-type InGaN growth, the p-In0.1Gao.9N/i-In0.1Ga0.9N/n-GaN junction structure is grown and fabricated into photodiodes.The spectral responsivity of the InGaN/GaNp-i-n photodiodes shows that the peak responsivity at zero bias is in the wavelength range 350-400 nm.