管傑雄臺灣大學：電子工程學研究所王源鉅Wang, Yuan-ChuYuan-ChuWang2007-11-272018-07-102007-11-272018-07-102004http://ntur.lib.ntu.edu.tw//handle/246246/57246紅外線偵測器在釵h民生，軍事，及科學上被廣泛應用的應用。其中的一些應用，如目標物辨識或是溫度感測，需要能夠多彩偵測的紅外線偵測器。在這篇論文中，我們提出一種新的結構是由超晶格耦合量子井組合而成。我們設計超晶格紅外線偵測器的偵測波長在6∼10μm，同時量子井紅外線偵測器的偵測波長是在11μm。在低偏壓低電流的情形下，我們希望從超晶格來的10μm波長響應能夠耦合量子井的響應。而這個新的結構能夠操作在光致電壓與光致電導兩種模式。 在光致電壓的模式下，我們可以觀察到3各明顯的波長響應。我們相信只有一個來自超晶格結構，另外兩個來自量子井結構。隨著溫度改變，響應會隨著溫度改變。在短波長的部分，會隨著溫度升高；至於長波長的部分，則是會被抑制。我們可以觀察到這種光致電壓的現象直到80K。 在光致電導的模式下，因為我們設計的特殊結構，所以超晶格紅外線偵測器只可以被操作在低負電壓底下。我們希望操作在低負電壓時，超晶格的響應能夠耦合量子井的響應，讓我們同時能夠觀察到超晶格與量子井的耦合訊號。如此一來，我們就可以得到一個寬頻譜的響應。 藉由這個結構，我們的偵測器將能操作在光致電壓與光致電導兩種不同的模式，而且將會具有電壓操控的特性。The infrared photodetectors are important in many civilian, military and scientific applications. Some of them, for example temperature sensing and target discrimination, requires the infrared photodetector to be equipped with the ability of multicolor detection. In this thesis, a new structure of superlattice infrared photodetector(SLIP) coupled to a quantum well infrared photoedetector (QWIP) is investigated. The SLIP is designed for wavelength 6~10µm detection while the QWIP is for wavelength around 11µm. The perspective is the photoresponse of 10µm from superlattice can couple to quantum wells under low bias with low dark current. The new structure can be operated under both photovoltaic and photoconductive mode. For the photovoltaic mode, three different photoresponse peaks from different transitions can be observed. It is believed that one peak is from SLIP and the other two are from QWIP. The lineshapes of the photoresponse will be changed with different temperature. As the temperature rising, the short wavelength photoresponses will be enhanced but the long wavelength ones are suppressed.The photovoltaic effect can be observed until 80K. For the photoconductive mode, because of the special structure, the photoresponse from SLIP is shown only under low negative bias. The perspective is the photoresponse from superlattice can couple to quantum wells under low negative bias and the photoresponse from both SLIP and QWIP can be observed simultaneously. In this way, we hope we can observe a broadband response. Based on this structure, our detector with photovoltaic and photoconductive dual-mode operation and properties of voltage-switchable and voltage-tunable can be achieved.Abstract i 1 Introduction 1 2 Infrared Photodetector 5 2.1 Introduction . . . . . . . 5 2.1.1 Blackbody Radiation . . 6 2.1.2 Intersuband Transition . 7 2.2 GaAs/AlxGa1−xAs Multiple Quantum Wells and Superlattice . . 8 2.2.1 Quantum Well Photoconductive Detectors . . . 8 2.2.2 Superlattice Infrared Photodetector . . . .. 9 2.3 PhotovoltaicMode . . . . . . . . . . . . . . 10 2.3.1 Photovoltaic Quantum Well Infrared Photodetector . . 11 2.3.2 Photovoltaic Superlattice Infrared Photodetector . . . . . 12 3 Fabrication Process and Measurement of Devices 13 3.1 Fabrication Process of the Single Photodetector . . . . . . . . . . 13 3.1.1 Sample Cleaning . . . . . . . . . . . . . . 14 3.1.2 Lithography . . . . . . . . . . . . . . . . 14 3.1.3 Wet Etching . . . . . . . . . . . . . . . . 15 3.1.4 Metal Evaporation and Lift-off. . . . . . . 15 3.1.5 Annealing . . . . . . . . . . . . . . . . . 16 3.1.6 Polishing Facet and Wire Bonding . . . . .. 16 3.2 Instrument Setup and Characterization Measurments . . . . . . . 18 3.2.1 Spectral Response . . . . . . . . . . . . . 18 3.2.2 Responsivity . . . . . .. . . . . . . . . . 19 3.2.3 I-V characteristics . . . .. . . .. . . . . 20 3.2.4 Detectivity . . . . . . . . . . . . . . . . 22 4 Experimental Results Of Detector Characteristics 25 4.1 Detector Structure . . . . . . . . . . . . . . 25 4.2 Design Prinicples . . . . . . . .. . . . . . . 27 4.2.1 Photovoltaic Mode . . . . . . .. . . . . . 29 4.2.2 Photoconductive Mode . . . . . . . . . . . . 31 4.3 Experimental Results Of Detector Characteristics . . . . . . . . . 34 4.3.1 Spectral Reponsivity . . . . . . . . . . . . 34 4.3.2 I-V characteristics . . . . . . .. . . . . . 44 4.3.3 Detectivity . . . . . . . . . . . . . . . . 44 5 Discussion 55 5.1 Photovoltaic Mode . . . . . .. . . . . . . 55 5.2 Photoconductive Mode . . . . . . . . . . . . . 59 6 Conclusion 678000535 bytesapplication/pdfen-US光致電導紅外線光致電壓超晶格量子井InfraredPhotoconductivePhotovoltaicSuperlattice[SDGs]SDG7thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/57246/1/ntu-93-R91943099-1.pdf