Characteristics of an Indium-Rich InGaN p–n Junction Grown on a Strain-Relaxed InGaN Buffer Layer

An indium-rich InGaN p-n junction is grown on a strain-relaxed InGaN buffer layer. The results show that the n-InGaN is grown coherently on the buffer layer but the p-InGaN layer exhibits a partial strain relaxation. The fabricated InGaN p-n junction has a low reverse leakage current density on the order of 10^?8 A/cm² within the measured voltage range, and exhibits a wide spectral response due to the presence of band tail states or deep level states which origin from indium composition fluctuation or various defects. The measured peak responsivity at 438 nm is 31 mA/W at zero bias and reaches 118 mA/W at 3 V reverse bias. In addition, the Raman spectra of the p- and n-type InGaN alloys are also analyzed.