Control of Operating Wavelength and Linewidth in LWIR InAs/InGaAs Dots-in-a-Well Detectors

摘要

Long-wave infrared (LWIR) detectors are in demand for myriad applications ranging from night vision cameras to chemical spectroscopy. In the past few years, LWIR detectors based on inter-subband transitions in self-assembled quantum dots (SAQDs) have exhibited normal incidence sensitivity, lower dark current and higher operating temperatures. However, the main problem with the QD detectors has been the lack of a control mechanism for accurately predicting the operating wavelengths due to the complicated dependence of the size and shape of the dot on the growth conditions. We have recently reported dots in a well (DWELL) detectors in which the InAs dots are placed in an InGaAs well, which in turn is surrounded by GaAs barriers (Fig. 1). This design not only reduces thermionic emission by lowering the ground state of the dot with respect to the GaAs bandedge, it also enables us to control the operating wavelength of the detector. The control of the operating wavelength is the subject of this paper.