Negative persistent photoconductivity in an InAs/GaSb quantum well

Abstract We performed magneto-resistance measurements on a semi-metallic InAs–GaSb quantum well. By shining visible light on the sample, a Negative Persistent Photoconductivity effect (NPPC) was observed. Overnight illumination reduced the electron density of the sample from 9.54×10 11 cm −2 to 9.04×10 11 cm −2 . A possible explanation for this effect is being sought in interface defect states.