上海科技大学知识管理系统

Improving the signal-to-noise ratio of infrared photodetectors is a primary goal especially for those operating in the long wavelength range. Optical design in the sub-wavelength scale provides a feasible routine toward this purpose, previous efforts mainly concentrated on integrating metallic antennas and plasmonic cavities with light absorption materials like semiconductor quantum wells (QWs). This study presents an all-dielectric way that can profit the electrical and photoelectric performance of detector concurrently. By fabricating the multiple QWs into linked micro-pillar arrays, the device yields 2.3 times enhanced responsivity at 12.55 μm relative to that of the 45° mesa counterpart, meanwhile the dark current density is found to decrease by 5.7-fold at -2.5 V and 50 K. These help to elevate the background-limited infrared photodetection temperature (TBLIP) of the micro-pillar array QW photodetector by 4.0 K.