The analysis of the performance for P-p-n and N-n-p hetero- and homojunction GaSb/Ga0.8In0.2As0.19Sb0.81 photodetectors

In this paper, the performance is analyzed for the P-1-p(2)-n and N-1-n(2)- p hetero- and homojunction GaSb/Ga0.8In0.2As0.19Sb0.81 photodetectors opera ted at 300 K, based on the incident wavelength and the parameters of GaSb a nd Ga0.8In0.2As0.19Sb0.81 The analyzed results show that the detectivity is much higher with the light incident first through the p-type than first th rough the n-type Ga0.8In0.2As0.19Sb0.81 for both structures. In addition, t he carrier concentration of GaSb should be as low as possible to reduce the tunneling noise through the P-1-p(2) and N-1-n(2) heterojunctions. With th e same condition for the two structures, the N-1-n(2)-p structure is more a dvantage than the P-1-p(2)-n structure because the high P-1-p(2) heterojunc tion recombination velocity increases the Auger and radiative noise mechani sms, which limit the performance of photodetectors.