GaInNAs p–i–n Photodetectors with Multiquantum Wells Structure

Abstract

GaInNAs/GaAs p–i–n photodetectors with 3 and 15 periods multiquantum wells (MQW) as the i-layer have been grown by metal–organic vapor-phase epitaxy (MOVPE). The cutoff wavelength of spectral responsivity occurs at around 1150 nm and reflects the transition energy of the GaInNAs/GaAs MQW. Because of to the good crystal quality that the devices with three periods MQW have, a two orders of magnitude increase in the responsivity rejection ratio is realized between 1150 and 1250 nm at a reverse bias of 2.0 V. The junction breakdown voltage is obtained at a reverse bias of 18.4 V. The ideality factor indicates that the conduction mechanism is dominated by the diffusion process, and the defect scattering effect caused by the misfit dislocations is only slight. On the other hand, the device with 15 periods MQW induces a higher value of misfit dislocations, and shows a partial relaxation phenomenon and thus it shows relatively poor characteristics.