Proton Irradiation Effect Study Of InAs/GaSb Type-Ⅱ Superlattice Infrared Detectors

In recent years,researchers domestic and international have conducted extensive and thorough investigations into the InAs/GaSb type-Ⅱ superlattices(T2SLs)material systems,such as designing the device structure,preparing the material,performing the device process,and investigating the dark current mechanism,among other things.They have made a series of research progress,which has the initial ability to meet a variety of application scenarios and become one of the best choices for third-generation infrared detectors.In particular,in the long-wavelength band,theoretical studies have demonstrated that the InAs/Gasb T2 SLs have better operational stability,reliability,and stronger irradiation resistance than the mercury cadmium telluride(Hg Cd Te)infrared detectors,which are expected to replace the Hg Cd Te infrared detectors in the future for space applications in the first place.Therefore,this paper combines groundbased irradiation experiments and the SRIM(Stopping and Range of Ions in Matter)computer simulation method to investigate the proton irradiation effect of InAs/GaSb type-Ⅱ superlattice infrared detectors,laying the foundation for the application of T2 SLs infrared detectors in the space field.The main contents of the study are as follows:(1)The SRIM program is used to simulate the irradiation effects of proton irradiation on InAs and GaSb materials and InAs/GaSb type-Ⅱ superlattices.The damage regions and irradiation damage mechanisms formed by proton irradiation in the two materials are analyzed concerning the basic parameters and information on the range and stopping power of incident protons in InAs and GaSb materials.(2)The irradiation damage to InAs/GaSb type-Ⅱ superlattices and multilayer target materials by protons with energies in the range between 0.01 and 1 MeV is investigated.The SR(Ions Stopping and Range Tables)module is used to compute tables of the injection depth of protons in the target material to determine the range and stopping principal at different energies.At the same time,the TRIM(Transport of Ions in Matter)module is used to calculate the defects,energy damage,and concentration of incident protons in the superlattice material at different irradiation fluences,as well as the displacements per atom(DPA),which measures the degree of irradiation damage.In addition,the distribution of displacement damage induced by proton irradiation in multilayer target materials with various energies is analyzed.(3)The effects of 2 MeV proton irradiation on the photovoltaic performance of InAs/GaSb type-Ⅱ superlattice long-wavelength infrared detectors are studied using ground-based irradiation experiments to simulate the space environment,and the dark current and the photocurrent before and after irradiation in the 300 K radiation background are analyzed and discussed.The results demonstrate that the dark current density of the detector increases by two orders of magnitude,and the quantum efficiency decreases by one order of magnitude after the irradiation of 2 MeV protons.At the same time,the dark current density increase rate of the small mesa size detector is much faster than that of the large ones with increasing proton irradiation fluences.(4)Simulations of the main structural layers of InAs/GaSb type-Ⅱ superlattice LWIR detectors are carried out in combination with SRIM simulation software.The interaction between 2 MeV protons and the main structural layer of the InAs/GaSb type-Ⅱ superlattice LWIR detector is investigated,and the damage effects arising from various irradiation fluences are further analyzed.The simulation results demonstrate that the irradiation damage degree DPA increases with the rise of irradiation fluences.At the same time,the irradiation damage obtained from SRIM simulations is consistent with the results produced by the photocurrent measurements,while the dark current measurements are identical only at small irradiation fluences.