金屬作為替代傳統雙極性電晶體(Bipolar Junction Transistor)的基極材料被認為有機會可以增加該主動式元件的共基極電流增益(α)從而得以提升共射極電流增益(β)並避免擊穿崩潰效應(Punch Through)。但是早期製程工藝極限使良好品質金屬薄膜最薄只能達到10 nm左右，並且於惰性金屬表面上成長半導體也是一項困難的技術，因此當時該設計被認為並無法達到設計初衷的預期。本研究成功製備出數奈米品質良好的鉑金屬薄膜，並利用氣流中斷法的原子層沉積系統(Atomic Layer Deposition, ALD)藉由控制良好的自我侷限效應(Self-limited Effect) 成功於該惰性金屬表面成長出品質良好的單原子層氧化鋅(Monolayer Zine Oxide)。
極薄鉑金屬三端元件由兩個蕭特基接面(Schottky Junction)所組成。本研究製備的蕭特基接面漏電較小，且皆是以電子作為主要傳輸載子，因此該三端元件得以防止射極發射之載子於基極產生復合的可能性，故此三端元件可表現出高達668的共射極電流增益(V_CB=4.5 V,V_BE=0.27 V)，與趨近於1的基極傳輸因子，這些良好的電性結果皆驗證了對於該元件設計的概念，且也突破前人的研究結果。
現今紅外光偵測研究主流之一為透過金屬吸收紅外光時，於金屬表面產生高能量的熱載子(Hot Carriers)，並搭配金半接面所形成的蕭特基接面分離，進而形成電訊號。根據此概念，本研究希望對於現今使用金屬作為吸收材料的紅外光偵測器進行定量與定性分析，以及對於紅外光偵測器的改良提出元件設計想法。紅外光偵測器的部分分成電性及光學兩部分討論。電性部分期望極薄鉑金屬三端元件以基極浮接的量測方式，基極鉑吸收光後產生熱電洞導致電位提升，並進而降低兩端能障，增進射極電子注入從而增加光電訊號。實際光電轉換實驗也確實觀察到主動元件相對於傳統被動光電元件，於大偏壓下光電訊號較大。光學部分則利用新設計的光學共振腔結構將極薄鉑金屬兩端元件吸收率大量增加從而達到高光電輸出。由光學模擬得出該光學共振腔可提升元件對紅外光光的吸收率一個數量級，並可實際光電量測結果也與此相呼應。
另外，本研究首次提出利用光霍爾(Photo Hall Effect)方式對紅外光於金屬激發出之熱載子(Hot Carriers)進行定性與定量分析。從霍爾電壓(Hall Voltage)的變化可以定性分析出獲得較多動能的載子為熱電子或熱電洞。再藉由所推導出之公式進一步將光霍爾量測結果定量分析，推算出金屬於吸收紅外光後產生熱載子的轉換效率。由結果可知，目前主流紅外光偵測器所使用的金屬金相對於其他金屬確實具有非常高的熱載子轉換效率。由該結果可預期若是將本研究提出的元件設計材料由鉑替換為金，則元件響應度將至少有五個數量級的提升。
本研究結果除了突破前人認為金屬材料無法作為三端元件基極的想法，也為目前使用金屬為光吸收材料的紅外光偵測器提供材料選擇與元件特性提升的設計方法。

Metal as the base material for conventional three-terminal transistors was considered to enhance the common base current gain (α), improving the common emitter current gain (β), and to prevent breakdown effects. However, early processing technology constraints limited the thickness of high-quality metal films to around 10 nm, and semiconductor growth on inert metal surfaces posed substantial challenges, rendering the original design seemingly unattainable. In this study, a few-nanometer thick, high-quality platinum metal film was successfully prepared. Subsequently, the atomic layer deposition (ALD) system with interrupted-flow method achieved good control over the self-limited effect. This method successfully grew a high-quality monolayer zinc oxide (Monolayer ZnO) on the inert metal surface.
The three-terminal device is constructed with two Schottky junctions and has been characterized to have low leakage and predominant electron transport. As a result, the three-terminal device avoids the carrier recombination phenomenon in the base, yielding a remarkable common emitter current gain of up to 668 (V_CB=4.5 V,V_BE=0.27 V) and a base transport factor approaching 1. These electrical results verify the device design concept and make the breakthrough of ultra-thin metal-based three-terminal device.
Currently, research in the field of infrared light detection is concentrated on the generation of high-energy hot carriers on metal surfaces upon absorption of infrared light. These carriers are then separated by built-in electric field of Schottky junction for generating electrical signal. This study seeks to quantitatively and qualitatively analyze infrared detectors using metal as the absorption material and suggests improvements in device design and material selection. The improvement of the infrared light detector involves discussions in electrical and optical parts. The ultra-thin platinum metal three-terminal device is measured with base floating. Platinum absorbs light and generates hot holes. These hot holes raise the base voltage and reduce the Schottky barrier at both ends. This phenomenon improves the emitter injection, increasing the photoelectric signal. The optical-electrical experiment confirms this concept. In the optical optimization part, a newly designed optical resonator structure significantly increases the light absorption of the ultra-thin platinum metal diode, leading to an improved photoelectric signal. Optical simulations indicate an order of magnitude enhancement in light absorption, which is consistent with the result of experimental measurement.
Furthermore, this study proposes a new method, the optical Hall method, for the qualitative and quantitative analyses of hot carriers excited by infrared light in metal surface. Variations in Hall voltage can qualitatively indicate hot carriers in metal as hot electrons or hot holes. Additionally, a derived formula can calculate the hot carrier generation rate in the metal under infrared light illumination by optical Hall measurement. The results confirm the excellent hot carrier conversion efficiency of gold which is a commonly used material in mainstream infrared detectors. Consequently, if gold can be used as the metal material in the proposed device design, it can be expected to increase the responsivity of the device by at least five orders of magnitude.
This study addresses the issues about the conventional thinking that ultra thin metals are unsuitable for being the base material of three-terminal devices, and offers valuable insights into material selection and device design for metal-based infrared light detectors.

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