管傑雄臺灣大學：電子工程學研究所王智立Wang, Chih-LiChih-LiWang2007-11-272018-07-102007-11-272018-07-102004http://ntur.lib.ntu.edu.tw//handle/246246/57534由於超晶格中內部能階的吸收波長對應於遠紅外線的波長範圍，因此超晶格紅外線偵測器吸引了釵h人的注意，使得超晶格紅外線偵測器在釵h民生，軍事，及科學上被廣泛的應用。在這篇論文裡，我們研究的結構是兩個不同週期數的超晶格中間嵌入一個電流阻擋能障層。我們設計兩個相似的偵測器比較他們的特性。其中一個偵測器,命名為D3，擁有1000奈米的電流阻擋層。另外一顆偵測器,命名為D6,包含300奈米的電流阻擋層,這兩個偵測器的超晶格結構除了摻雜濃度的不同外其餘皆相同。這種雙超晶格的架構可透過改變電壓極性在兩個光譜區間轉換光譜的響應。在每個光譜區間的光響應強度也可以利用電壓的大小來調整。 藉由簡單的製程步驟，以及量測儀器的架設，我們對元件做了一些有關電性、光學特性的量測。我們兩個偵測器的光響應在長波長範圍皆會隨著溫度的上昇而增加，我們認為這是由於熱激發的效應。我們也比較這兩顆偵測器的響應、光電流與暗電流，我們認為薄電流能障光偵測器的光響應，是受到在電子在第二迷你能帶的群速所影響，而厚電流能障偵測器的光響應主要是受到電子被激發到第二微能階的能量影響；除此之外，厚的電流能障，不僅會使得暗電流降低，同時也會降低光電流與光響應的大小，因此厚能障與薄能障偵測器的偵檢率皆在同一個倍率。The superlattice infrared photodetectors (SLIP) have drawn much attention since the observation of intersubband absorption in the far infrared region. It may be useful in many civilian, military, and scientific applications. In this thesis, we investigate the SLIP with the structure containing a current blocking layer embedded between two superlattice with different period numbers. We have designed two similar detectors to compare the performances. One of the detectors called D3 contains the 1000nm blocking barrier. The other called D6 contains the 300nm bolocking layer, while the superlattice structure of these two samples are the same except the doping density. This double-superlattice structure shows switchable spectral responses between two spectral regions by changing the voltage polarities. The photoresponse in each spectral region is also tunable by the magnitude of the applied voltage. By the simple fabrication process of samples into devices, and the measurement setup, we could measure the electrical and optical properties of our devices. Both of our detectors’ responsivity will be increased at long wavelength range as the temperature raise. This is due to the thermal excitation effect. We have compared the rsponsivity, dark current and photocurrent of these two samples and it is concluded that the responsivity from the sample with thin blocking barrier is affected by the group velocity at the second miniband and the responsivity of the thick barrier one is affected by the energy of the excited electron at second miniband. The thick blocking barrier will not only reduce the dark current but also the responsivity and photocurrent. Therefore, the detectivity for the thick barrier SLIP is at the same order for the thin one.Chapter 1 Introduction (P.3) Chapter 2 Background Introduction (P.6) 2.1 Fundamentals of QWIP (P.6) 2.1-1 Blackbody Radiation (P.6) 2.1-2 Multiple Quantum Well (P.7) 2.1-3 Superlattice Structure (P.8) 2.1-4 Superlattice Infrared Photodetector (SLIP) and functions of the current blocking barrier (P.10) 2.1-5 Relaxation and scattering in the second miniband (P.11) 2.2 The group velocity at the second miniband (P.12) 2.3 Introduction of FTIR (P.13) Chapter 3 Fabrication Process and Measurement of Devices (P.17) 3.1 Fabrication Process of the Photodetector (P.17) 3.2 Instrument Setup and Measurement (P.22) 3.2-1 Current-Voltage Measurement (P.22) 3.2-2 Spectral Response (P.24) 3.2-3 Responsivity (P.25) 3.2-4 Noise Equivalent Power (NEP) and Detectivity D* (P.27) Chapter 4 Experiment Result and Discussion (P.30) 4.1 The experimental data of D3 (the sample with the thick current blocking barrier (P.30) 4.1-1 Sample Description (P.30) 4.1-2 The operational mechanisms (P.33) 4.1-3 Current-Voltage Characteristic (P.34) 4.1-4 Responsivity (P.35) 4.1-5 Detectivity (P.41) 4.2 The experimental data of D6 (the sample with the thin current blocking barrier (P.44) 4.2-1 Sample Description (P.44) 4.2-2 Current-Voltage Characteristic (P.46) 4.2-3 Responsivity (P.47) 4.2-4 Detectivity (P.52) 4.3 Common trend- The responsivity under different temperature (P.54) 4.4 Comparisons between D3 and D6 (P.61) 4.4-1 The dark current and photo current (P.61) 4.4-2 The effect of the period numbers and blocking barrier width (P.64) 4.4-3 Detectivity (P.71) Chapter 5 Conclusion (P.74)3950901 bytesapplication/pdfen-US偵測器週期數能障寬度超晶格紅外線period numbersuperlatticeinfrareddetectorbarrier widththesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/57534/1/ntu-93-R91943035-1.pdf