Study of InGaAs/InAlAs avalanche photodiodes grown on InP

In this paper, we are report an avalanche photodiodes (APD) with an InGaAs absorption region and an InAlAs avalanche region. Devices are designed with separate absorption, grading, charge, and multiplication (SAGCM) layers on InP substrates, which are demonstrated to detect 1550 nm wavelength light. The epilayers of the APD devices are grown by a Veeco Gen 930 MBE system. The quality of epilayers is good which shown in the surface morphology characterized by AFM. The root mean square (RMS) of surface morphology is only 1.4Å.Operating at room temperature and in the linear mode, the APD achieved a dark-current level of 2.7uA/mm²,and a maximum gain of M>300 is demonstrated.