长波和甚长波及其双色InAs/GaSb二类超晶格红外探测器的研究进展

本文报道了基于InAs/GaSb二类超晶格实现长波、甚长波及窄带长波/甚长波双色红外探测器的研究,生长的材料具有极高的材料质量.长波探测器单管器件在77 K条件下50%截止波长为9.6μm,峰值响应为3.2 A/W,峰值量子效率为51.6%;甚长波红外探测器单管器件在77 K条件下50%截止波长为14.5μm,量子效率为14%,热噪声限制的探测率为4.3×109 cm Hz1/2 W-1.通过改变偏压极性实现双色探测的窄带型长波/甚长波InAs/GaSb二类超晶格红外探测器两端器件,偏压小于0 V时在长波区工作,偏压大于40 mV时,在甚长波区工作.具体来说,偏压为-0.1 V时,器件光响应50%截止波长为10μm;而偏压为40 mV时,器件光响应50%截止波长为16μm.对于长波光响应,δλ/λ为44%,对于甚长波响应,δλ/λ为46%.甚长波对长波的串音为9.9%,长波对甚长波的串音为11.8%.

Long wavelength,very long wavelength and narrow-band long-/very-long wavelength two-color type-II InAs/GaSb superlattice photodetectors

We have demonstrated a long wavelength （LW）, a very-long wavelength （VLW） and a narrow-band two-color LW/VLW photodetectors using type-II InAs/GaSb superlattice （SL） materials. For all the detection wavelengths, very high-quality type-II InAs/GaSb SL materials have been grown by molecular beam epitaxy. For the LW device, at 77 K, the achieved 50% cutoff wavelength is 9.6 μm and the maximum response is at 7.7 μm with the responsivity of 3.2 A/W. For the VLW device, at 77 K, the 50% cutoff wavelength is 14.5 μm and the corresponding quantum efficiency is 14%. The Johnson noise limited detectivity D＊ is 4.3×10^9 cm Hz^1/2 W^-1 at 14.5 μm. For the first time, we demons- trate a narrow-band two-color detector using type-II InAs/GaSb SL strctures. The LW/VLW two-color detector is a two-terminal device and the detection is achieved by changing the bias polarity. The device responds to the LW range when the bias voltage is smaller than 0 V while it works for the VLW range when the bias voltage is larger than 40 mV. Concretely, at 77 K, the 50% cutoff wavelength is 10μm when the bias voltage is -0.1 V, and is 16 μm when the bias voltage is 40 mV. The achieved 82/2 is 44% for the LW photoresponse and is 46% for the VLW photoresponse. The spectral crosstalk of the VLW band to the LW band is 9.9% while that of the LW band to the VLW band is 11.8%.