Unambiguous determination of carrier concentration and mobility for InAs/GaSb superlattice photodiode optimization

Abstract

In this communication we report on electrical properties of nonintentionally doped (nid) type II InAs/GaSb superlattice grown by molecular beam epitaxy. We present a simple technological process which, thanks to the suppression of substrate, allows direct Hall measurement on superlattice structures grown on conductive GaSb substrate. Two samples were used to characterize the transport: one grown on a semi-insulating GaAs substrate and another grown on n-GaSb substrate where a etch stop layer was inserted to remove the conductive substrate. Mobilities and carrier concentrations have been measured as a function of temperature (77–300 K), and compared with capacitance-voltage characteristic at 80 K of a photodiode comprising a similar nid superlattice.

Investigation of the lower temperature SiO2 surface passivation technology on InAs/GaSb superlattice detectors

“…The fitting parameters whose values that are taken from being temperature dependent, were extracted from Hall measurements [10].…”

Growth And Characterization Studies Of Advanced Infrared Heterostructures

“…4b are the responsivities of each of the devices at moderately high reverse bias where the response at 3.6 µm starts to saturate. The saturation responsivity increased from ~0.11 A/W at 80 K, which corresponds to an absorption quantum efficiency of 13.3%, to ~0.13 A/W at 200 K. It is believed that the decrease of zero-bias responsivity at moderate temperatures is due to the background carrier concentration change and p-type to n-type inversion [14]. Such change could introduce some band-bending, which would alter the band alignment and could produce unwanted carrier blocking barriers and deteriorate the zero-bias photo-carrier transport.…”

Radiometric characterization of type-II InAs/GaSb superlattice (t2sl) midwave infrared photodetectors and focal plane arrays

“…R is the reflectance at the air/T2SL interface and set equal to 0.3. x 1 and x max -x 2 the thickness of the quasi neutral zone N and the quasi neutral zone P and depend on the bias voltage. The InAs-rich SL structure is n-type residual with hole minority carriers [6]. We determined the hole diffusion length L h by fitting the equation with the measured QE, using L h as the only adjustable parameter.…”

“…As holes have a short diffusion length, the collection process is not optimal. One solution would be to change the minority carriers into electrons, which have a better diffusion length [6]. This can be done by slightly P-doping the active zone, leading to a P + P -N junction as used in [7] to optimize LWIR structures.…”