- 學位論文
以化學浴沉積法成長氧化亞銅摻雜鎳薄膜特性分析
Study on the Characteristics of Ni-doped Cuprous Oxide Films Prepared by Chemical Bath Deposition
摘要
本實驗利用化學浴沉積法成長氧化亞銅(n-Cu2O)以及摻雜鎳氧化亞銅(n-Cu2O:Ni)於銅基板上。其作法是將銅基板置於硫酸銅溶液燒杯中，並利用加熱器以熱傳導的方式控制反應溶液的溫度約為100˚C，化學浴沉積法最大優點為製程簡單。 由IV量測出未摻雜的氧化亞銅薄膜電阻係數為75Ω-cm，為了降低n-Cu2O薄膜的電阻係數而增加其導電率在溶液中添加NiSO4作為摻雜使Ni原子進入晶格中取代銅的位置[NiCu]，當其[Ni]/[Cu]莫爾比例在0.2時其電阻係數會下降到51Ω-cm。將n-Cu2O:Ni薄膜在保護氣體N2加O2之氣體環境下進行退火處理之後，其薄膜電阻係數更為下降達到45.76Ω-cm。 從XRD圖中已證明採用化學浴沉積法所形成半導體薄膜均為Cu2O晶相並無CuO之晶相產生，其從優取向為(111)面，經過溫度550˚C回火處理後，(111)信號可增強2倍以上。 根據低溫(10K)PL量測發現其PL光譜具有兩個波峰分別為720nm(1.72eV)和647nm(1.91eV)。1.72eV的波峰為氧空缺(VO)所形成的束縛激子(bound exciton)發光，而1.91eV波峰則為鎳[Ni]取代銅[Cu](即NiCu缺陷)所形成的激子發光，氧空缺與NiCu缺陷均為N型導電機制。將n-Cu2O:Ni薄膜進行回火處理溫度高於350˚C其PL光譜會出現906nm(1.37eV)波段，導電型態轉變成P型。當回火溫度到達550˚C時，PL光譜中的1.91eV波峰消失不見，而1.72eV波峰強度減弱，另外產生1.37eV波峰強度增高成為最強之波峰，此現象推測可能在回火處理時薄膜晶格中的鎳原子蒸發離開而形成銅空缺(VCu)，當溫度越高鎳原子蒸發程度越強，銅空缺強度就越強，使得在PL光譜中1.37eV波峰強度成為最強，而銅空缺為形成P型的導電機制。
並列摘要
In this study, the cuprous oxide films and the Ni-doped cuprous oxide films were prepared by chemical bath deposition. The copper substrate is placed in a beaker, and using the heater to control reaction solution temperature about 100˚C by heat transfer. The advantage of chemical bath deposition process is simple and low cost. IV measurements show that the undoped copper oxide film resistivity is 75Ω-cm. NiSO4 is added as a dopant ions into solution to reduce the resistivity of the n-Cu2O films, the Ni ions get into crystal lattice to replace copper[NiCu]. Resistivity before annealing is 51Ω-cm meanwhile the mole ratio[Ni]/[Cu] is 0.2 .After annealing the resistivity of n-Cu2O:Ni film is reduced to 45.76Ω-cm when chamber is filled with gas O2 and N2. It has been proved that the semiconductor film crystal orientation grew by CBD is not CuO but Cu2O, its preferred orientation is (111).After annealing temperature reached 550˚C and above, the intensity of peak (111) can be enhanced more than 2 times. According to low temperature(10K) PL measurement showed that spectrum include two peaks at 720nm (1.72eV) and 647nm (1.91eV) respectively. The 1.72eV peak is bound exciton composed by oxygen vacancies (VO). The other peak 1.91eV is exciton that composed by Ni replaced Cu (NiCu). Both oxygen vacancies and NiCu are main reasons of n-type film. PL spectrum results will show a peak 906nm (1.37eV) when the annealing temperature is above 350˚C, and the Cu2O:Ni film will change to p-type. When annealing temperature reaches 550˚C ,the 1.91eV peak will vanished, intensity of 1.72eV peak will decreased also, the peak at 1.37eV will be the highest one. This phenomenon can be conjectured that Ni atoms in crystal were steamed and becoming copper vacancies (VCu). With higher temperature ,the degree of nickel atoms will be steamed much more, this will make intensity of copper vacancies more higher, and the peak at 1.37eV will become the highest peak in the PL spectrum, the copper vacancies is the mechanism of p-type.