Comparative evaluation of InAs/GaSb superlattices for mid infrared detection: p-i-n versus residual doping


Korkmaz M., Kaldirim M., Arikan B., SERİNCAN U., ASLAN B.

SEMICONDUCTOR SCIENCE AND TECHNOLOGY, cilt.30, 2015 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

We report on the opto-electronic characterization of an InAs/GaSb superlattice (SL) midwave infrared p-i-n photodetector structure (pin-SL) in comparison with the same structure with no intentional doping (i-SL). Both structures were grown on an n-GaSb substrate using molecular beam epitaxy. The nominally undoped structure (i-SL) presented p-i-n like behavior and showed a photovoltaic mode photoresponse due to the residual doping and native defects in this material system. For similar to 77 K operation, 0.76 and 0.11 A W-1 responsivity values were obtained at 4 mu m from the pin-SL and i-SL structures, respectively. Activation energy analysis showed that the recombination current was dominant in both structures but different recombination centers were involved. The same i-SL structure was also grown on a semi-insulating (SI)-GaAs substrate to study the contribution of the substrate to the carrier density in the SL layers. Temperature dependent Hall effect measurements showed that the nominally undoped structure presented both n-type and p-type conductivities; however, the temperature at which the carrier type switched polarity was observed to be at higher values when the i-SL structure was grown on the SI-GaAs substrate. In addition, a higher carrier density was observed for i-SL on the GaSb substrate than on the GaAs substrate.