Metastability and polarization effects in a p n heterojunction device due to deep states

Unusual metastable and polarization behavior has been observed for Al0.48In0.52As/ Ga0.47In0.53As avalanche photodiodes by capacitance spectroscopy. The metastability arises from interplay of the heterojunction barrier with defects in the Al0.48In0.52As layer. Defect occupation controls the reverse bias characteristics of the device while the heterojunction presents a barrier to carrier capture by the defects.