201116648 六、發明說明： 【發明所屬之技術領域】 本發明係有關於光吸收層之製法，且特別是有關於一 種CIGS太陽能電池之光吸收層之製法。 【先前技術】 半導體材料具有特殊的能階大小（band gap)，可藉由調 控材料組成而改變半導體之能隙，因此可將其應用作為光 籲 電元件（photoelectronic device)之光吸收層。 於各種半導體材料中，其中以具有黄銅礦(chalcopyrite) 結構的IB-IIIA-VIA族化合物特別受到重視，其可製成薄 膜應用於硒化銅銦鎵電池(Cu(In,Ga)Se2，CIGS)中，且具有 不錯的光電轉換效率。 目前製作IB-IIIA-VIA族化合物之薄膜的方法可分為 真空和非真空製程，真空製程包括共蒸鍍 (co-evaporation)、濺鍍(sputter)等製程，而非真空製程包括 鲁奈米粒子槳·料塗佈法(nano-particle printing)、溶液反應法 (solution-base deposition)以及溶液·凝膠法（s〇l-gei)。 真空製程為最為成熟的製備方法，然而缺點在於設備 建置與維護成本高。奈米粒子漿料塗佈法具有設備建置與 維護成本低，前驅物薄膜形成快速等優點，但元素組成均 勻性以及熱處理後薄膜結晶的品質則為一大難題。溶液反 應法則因其反應須使用無水聯胺，具有高度危險性。溶液 凝膠法能有效產生所需的IB_IIIA_VIA族太陽能電池吸收 層則驅物/專膜，但其有薄膜平整性以及副產物殘留等問題。 201116648 US2008/0280030揭露一種光吸收層之製法，其將 Cu(OH)2漿料與Ιπ(ΟΗ)3漿料用印刷的方式（printing)疊合， 之後石西化（selenization)處理得到IB-IIIA-VIA光吸收層。 Vidyadharan et al. {Solar Energy Materials and Solar 57(1998W7-W)揭露一種光吸收層之製法，其利用化 學浴沉積法（chemical bath deposition，CBD)沉積單層 CuInSe2 薄膜。201116648 VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method of fabricating a light absorbing layer, and more particularly to a method of fabricating a light absorbing layer of a CIGS solar cell. [Prior Art] A semiconductor material has a special band gap, and the energy gap of the semiconductor can be changed by adjusting the composition of the material, so that it can be applied as a light absorbing layer of a photoelectronic device. Among various semiconductor materials, among them, IB-IIIA-VIA compound having a chalcopyrite structure is particularly emphasized, and it can be used as a film for a copper indium gallium selenide battery (Cu(In,Ga)Se2, CIGS), and has a good photoelectric conversion efficiency. The current methods for making films of IB-IIIA-VIA compounds can be divided into vacuum and non-vacuum processes, including vacuum co-evaporation, sputtering, etc. Particle-substrate printing, solution-base deposition, and solution-gel method (s〇l-gei). The vacuum process is the most mature preparation method, but the disadvantage is the high cost of equipment construction and maintenance. The nano particle slurry coating method has the advantages of low equipment construction and maintenance cost, and rapid formation of precursor film, but the uniformity of element composition and the quality of film crystallization after heat treatment are a major problem. The solution reaction method is highly hazardous because it requires the use of anhydrous hydrazine. The solution gel method can effectively produce the desired IB_IIIA_VIA solar cell absorber layer and the film/film, but it has problems such as film flatness and by-product residue. 201116648 US2008/0280030 discloses a method for preparing a light absorbing layer, which superimposes a Cu(OH)2 slurry with a Ιπ(ΟΗ)3 paste by printing, and then selenization to obtain IB-IIIA. -VIA light absorbing layer. Vidyadharan et al. {Solar Energy Materials and Solar 57 (1998 W7-W) discloses a method of depositing a light absorbing layer by depositing a single layer of CuInSe2 film by chemical bath deposition (CBD).
Bhattacharya et al {Solar Energy Materials and Solar J5(1998；M-抑)揭露一種光吸收層之製法，其利用 CBD 法，使用 Cu(N03)2、In(S03NH2)3、Ga(N03)3、 Na2SeS03、三乙醇胺（triethanolamine)、氨水(NH4OH)與氫 氧化鈉作為反應物，得到富含銅之前驅物（Cu-rich precursor)，之後再進行物理氣相沉積法（pvd)得到 CuInGaSe2單層光吸收層。 因此，業界亟需發展一種光吸收層之製法，其不但製 程簡單且可使CIGS電池具有不錯的光電轉化效率 (photo-electric conversion)。 【發明内容】 本發明提供一種光吸收層之製法，包括以下步驟：提 供一基板，以化學浴沉積法（chemical bath deposition, CBD) 形成一前驅物薄膜於該基板之上，其中該前驅物薄膜為一 IB-VIA族化合物與一 niA-VIA族化合物交錯沉積之複合 層；以及將該前驅物薄膜置於一氣體氣氛下進行一熱處理 201116648 製程以得到該光吸收層。 為讓本發明之上述和其他目的、特徵、和優點能更明 ...真易If τ文特舉出較佳實施例，並配合所附圖式，作詳 細說明如下： 【實施方式】 化 4·洛’几積法（Chemicai Bath Deposition，CBD)為一種 籲方便且製程穩定性高之沉積方法，利用該製程技術可達到 以簡單、低成本的技術製備IB_mA_VIA族太陽能電池吸 收層前驅物薄膜的目標。 請參見第1圖，該圖顯示本發明光吸收層之製作流 程，首先進行步驟101，提供一基板，其包括玻璃、高分 子基板等，而於基板之上包括金屬電極。接著，進行步驟 102，以化學浴沉積法（CBD)形成一前驅物薄膜於基板上， 此前驅物薄膜為一複合層’分別由步驟1〇2a、步驟1〇2b •製備而得。 睛參見步驟102a，以化學浴沉積法（Cbd)形成一 IB-VIA族化合物’其中IB-VIA族化合物包括硫化銅（CuS) 或硒化銅（CuSe)。沉積IB-VIA化合物之化學浴槽中包括含 有IB族陽離子之化合物、含有VIA族陰離子之化合物與 可與陽離子形成錯合物之錯合劑。IB族化合物包括IB族 之鹵化物、硝酸物、醋酸物與硫酸物，例如氣化銅（CuC12)、 石肖酸銅（Cu(N03)2)、硫酸銅（CuS〇4)、醋酸銅 201116648 (Cu(CH3C00)2) ’而上述化合物之選擇，並不限於上述提及 之化合物，其他含有IB族之化合物亦在本發明所保護之範 圍内。含有VIA族陰離子化合物為硫脲(thi〇urea，sc(NH2)2) 或硫代乙基胺(thioacetamide，SC(NH2)(CH3))。另外，錯合 劑為具有羥基(-0H)與胺根(_NH2)之鹼性溶劑，例如單乙醇 胺（monoethanol amine)、二乙醇胺（diethan〇1 amine)或三乙 醇胺（triethanol amine)。 沉積IB-VIA族化合物之化學浴槽的pH値範圍為約8 〜11，較佳為約9〜ίο，溫度為約2(rc〜5(rc，較佳為約 25°C〜35°C，反應時間為約1〇分鐘〜3〇分鐘，較佳為約15 分鐘〜25分鐘。 於一實施例中，配置 0.01MCuC12、0.05MSC(NH2)2 與1M單乙醇胺(MEA)，化學浴槽之pH值控制在114，溫 度控制在35°C，沉積約40分鐘，即可製得硫化銅（CuS)薄 膜。 步驟102b中，同樣以化學浴沉積法（CBD)形成一 IIIA-VIA族化合物於IB-VIA族化合物之上，其中iiiA-VIA 族化合物包括硫化銦（Ind3)、硒化銦（in2se3)、硫化鎵（Ga2S3) 或碼化鎵(Ga2Se3)。 沉積IIIA-VIA族化合物之化學浴槽中包括含有ΙΠΑ族 陽離子之化合物、含有VIA族陰離子之化合物與可與陽離 子形成錯合物之錯合劑。IIIA族包括鉬(In)、鎵(Ga)或上述 之組合，而IIIA族化合物包括ΠΙΑ族之鹵化物、硝酸物、 醋酸物與硫酸物，例如氣化銦GnCl3)、氯化鎵（GaCl3)、硝 酸銦（In(N03)3)、硝酸鎵（Ga(N〇3)3)、醋酸銦 201116648 (In(CH3COO)3)、醋酸鎵(Ga(CH3COO)3)、硫酸銦(In2(s〇4)3) 或硫酸鎵（Ga/SO4)3) ’而上述化合物之選擇，並不限於上 述提及之化合物，其他含有IIIA族之化合物亦在本發明所 保護之範圍内。含有VIA族陰離子化合物同上所述。另外， 錯合劑為包含羧基(_C00H)與羥基(_OH)之有機酸，例如酒 石酸（tartaric acid)或擰檬酸（citric acid)。 沉積IIIA-VIA族化合物之化學浴槽的pH値範圍為約 2〜6。’較佳為約3〜5，溫度為約5(rc〜8(rc，較佳為約6〇它 # 〜70°C，反應時間為約1小時〜3小時，較佳為約15小時〜2 5 小時。 於一實施例中，配置 〇.〇1 M inCl2、〇 MSC(NH2)(CH3)與 0.1 Μ 檸檬酸(citric acid)，化學浴槽之 pH值控制在3.7，溫度控制在70。(：，沉積1.5小時，即可 製得硫化銦(In2S3)薄膜。 完成上述步驟l〇2a與102b後，即可獲得前驅物薄膜， 此前驅物薄膜由兩層化合物所組成。於一實施例中，前驅 鲁物薄膜為硫化銅(CuS)層-硫化銦(In2S3)層。 此外’尚可重複步驟102a、102b，因此，可得到複合 層之結構，使基板之上形成大於兩層之前驅物薄膜。於另 一實施例中，形成五層結構，為硫化銅硫化姻 (In2S3)層-硫化銅（CuS)層-硫化铟（ΙηΛ)層-硫化銅（CuS) 層。前驅物薄膜沉積之層數可為兩層到多層，每一層之厚 度可以依據沉積的時間和溫度作調整，而總厚度一般為約 0.1 μηι〜2 μιη 〇 此處須注意的是，由於前驅物薄膜之後會進行熱處理 201116648 製程，而ΙΙΙΑ族-VIA族化合物於高溫下容易受熱分解，因 此於一較佳之實施例中，所形成之薄膜最好是單數層，上 下層由IB-VIA族化合物所構成。由上述製法得到之前驅物 薄膜，藉由能量分散式光譜儀（Energy Dispersive Spectrometer，EDS)進行元素分析，得知其m族與ΙΠΑ族 元素比例為約0.6〜1.0’較佳為約〇.8〜〇95。於一實施例中， 當沉積硫化銅-硫化銦（CuS-Inj3)前驅物薄膜時，其中鋼/ 銦比為約0.93。 習知技術中，使用化學浴沉積法製作單層之光吸收 層，然而，由於IB族離子（例如銅離子）與mA族離子（ 如銦離子）之沉積速度不同，同時進行兩種陽離子之化學浴 沉積時，會使得銅的含量明顯高於銦或鎵，進而使得光 收層之光電轉化效率不佳。而本發明分別配置適合兩種金 屬沉積之浴槽，分別控制浴槽之離子濃度、溫度、ρΗ值與 沉積時間，不但能對各層之含量作控制，且可最佳化兩 不同之前驅物薄膜。 之後，將前驅物薄膜進行熱處理製程，其中熱處理掣 程包括真空或非真空的加熱製程，其令非真空可於—般大 氣下、惰性氣體下進行加熱(如步驟1〇3)或含VIA族元素 的氣體(如步驟1〇4之硫化處理製程、步驟ι〇5之硒化處理 製程）。 請參見步驟103’將前驅物薄膜置於惰性氣體氣氛下 進行熱處理製程’以得到光吸收層，其中惰性氣體氣氛包 括·氣氣(N〗）、氣氣(Η〗）、氮氣(Ar)、一氧化碳（CO)、一>氣 化氮(NO)或上述之組合。 201116648 請參見步驟104,將前驅物薄膜置於硫化氫(h2S)或硫 (S)蒸氣中進行熱處理製程，而步驟中，將前驅物薄膜 置於硒化氫(H2Se)或硒（Se)蒸氣中進行熱處理製程。 最後，請參見梦驟106，當進行步驟103之熱處理製 程或104之硫化處理製私後’可得到三元合金之光吸收 層，例如銅銦硫。而少驟107，當進行步驟105之硒化處 理製成後，可得到四元合金之光吸收層，例如銅銦硫硒。Bhattacharya et al {Solar Energy Materials and Solar J5 (1998; M-Suppression) discloses a method for fabricating a light absorbing layer using the CBD method using Cu(N03)2, In(S03NH2)3, Ga(N03)3, Na2SeS03 , triethanolamine, ammonia (NH4OH) and sodium hydroxide as reactants, obtain copper-rich precursors (Cu-rich precursor), and then physical vapor deposition (pvd) to obtain CuInGaSe2 single-layer light absorption Floor. Therefore, there is an urgent need in the industry to develop a method for fabricating a light absorbing layer that is not only simple in process but also provides a good photo-electric conversion for CIGS cells. SUMMARY OF THE INVENTION The present invention provides a method for fabricating a light absorbing layer, comprising the steps of: providing a substrate, forming a precursor film on the substrate by chemical bath deposition (CBD), wherein the precursor film A composite layer in which an IB-VIA compound is interleaved with a niA-VIA compound; and the precursor film is subjected to a heat treatment 201116648 process under a gas atmosphere to obtain the light absorbing layer. The above and other objects, features, and advantages of the present invention will become more apparent from the aspects of the appended claims. 4·Chemicai Bath Deposition (CBD) is a convenient deposition method with high process stability. It can be used to prepare IB_mA_VIA solar cell absorber layer precursor film by simple and low cost technology. The goal. Referring to Fig. 1, there is shown a process for fabricating the light absorbing layer of the present invention. First, step 101 is performed to provide a substrate comprising glass, a high molecular substrate or the like, and a metal electrode is included over the substrate. Next, in step 102, a precursor film is formed on the substrate by chemical bath deposition (CBD), and the precursor film is a composite layer' prepared by the steps 1〇2a and 1b2b, respectively. Referring to step 102a, a IB-VIA compound is formed by chemical bath deposition (Cbd). The IB-VIA compound includes copper sulfide (CuS) or copper selenide (CuSe). The chemical bath in which the IB-VIA compound is deposited includes a compound containing a Group IB cation, a compound containing a Group VIA anion, and a complexing agent which can form a complex with a cation. Group IB compounds include halides of the Group IB, nitrates, acetates and sulfates, such as copper (CuC12), copper silicate (Cu(N03)2), copper sulfate (CuS〇4), copper acetate 201116648 (Cu(CH3C00)2)' and the selection of the above compounds is not limited to the above-mentioned compounds, and other compounds containing Group IB are also within the scope of protection of the present invention. The group VIA anion compound is thiourea (thi(ure), sc(NH2)2) or thioacetamide (SC(NH2)(CH3)). Further, the complexing agent is an alkaline solvent having a hydroxyl group (-0H) and an amine group (_NH2), such as monoethanol amine, diethan〇1 amine or triethanol amine. The chemical bath for depositing the IB-VIA compound has a pH range of about 8 to 11, preferably about 9 to ί, and a temperature of about 2 (rc to 5 (rc, preferably about 25 to 35 ° C, The reaction time is about 1 minute to 3 minutes, preferably about 15 minutes to 25 minutes. In one embodiment, 0.01MCuC12, 0.05MSC(NH2)2 and 1M monoethanolamine (MEA), pH of the chemical bath are configured. The value is controlled at 114, the temperature is controlled at 35 ° C, and deposition is about 40 minutes to obtain a copper sulfide (CuS) film. In step 102b, a IIIA-VIA compound is also formed in IB by chemical bath deposition (CBD). On the -VIA compound, wherein the iiiA-VIA compound comprises indium sulfide (Ind3), indium selenide (in2se3), gallium sulfide (Ga2S3) or gallium (Ga2Se3). The chemical bath in which the IIIA-VIA compound is deposited The invention comprises a compound containing a cation of a cation, a compound containing a group VIA anion and a complexing agent capable of forming a complex with a cation. Group IIIA includes molybdenum (In), gallium (Ga) or a combination thereof, and the group IIIA compound includes a lanthanum group. Halides, nitrates, acetates and sulfates, such as indium oxide GnCl3), gallium chloride (G aCl3), indium nitrate (In(N03)3), gallium nitrate (Ga(N〇3)3), indium acetate 201116648 (In(CH3COO)3), gallium acetate (Ga(CH3COO)3), indium sulfate (In2 (s〇4) 3) or gallium sulphate (Ga/SO4) 3) ' and the selection of the above compounds is not limited to the above-mentioned compounds, and other compounds containing a group IIIA are also within the scope of protection of the present invention. Containing Group VIA anionic compounds as described above. Further, the complexing agent is an organic acid containing a carboxyl group (_C00H) and a hydroxyl group (_OH), such as tartaric acid or citric acid. The pH of the chemical bath in which the Group IIIA-VIA compound is deposited ranges from about 2 to about 6. Preferably, it is about 3 to 5, and the temperature is about 5 (rc~8 (rc, preferably about 6 〇 it# to 70 ° C, and the reaction time is about 1 hour to 3 hours, preferably about 15 hours~ 2 5 hours. In one embodiment, 〇.〇1 M inCl2, 〇MSC(NH2)(CH3) and 0.1 Μ citric acid are disposed, the pH of the chemical bath is controlled at 3.7, and the temperature is controlled at 70. (:, deposition of 1.5 hours, a film of indium sulfide (In2S3) can be obtained. After completing the above steps l〇2a and 102b, a precursor film can be obtained, and the precursor film is composed of two layers of compounds. The precursor film is a copper sulfide (CuS) layer-indium sulfide (In2S3) layer. In addition, steps 102a and 102b can be repeated, so that the structure of the composite layer can be obtained, and more than two layers are formed on the substrate. In another embodiment, a five-layer structure is formed, which is a copper sulfide (In2S3) layer-copper sulfide (CuS) layer-indium sulfide (ΙηΛ) layer-copper sulfide (CuS) layer. Precursor film deposition The number of layers can be two to many layers, the thickness of each layer can be adjusted according to the time and temperature of deposition, and the total thickness is generally 0.1 μηι〜2 μιη 〇 It should be noted here that since the precursor film is subjected to the heat treatment 201116648 process, and the steroid-VIA compound is easily thermally decomposed at a high temperature, in a preferred embodiment, Preferably, the film is a single layer, and the upper and lower layers are composed of a compound of the IB-VIA group. The precursor film is obtained by the above-mentioned preparation method, and elemental analysis is performed by an Energy Dispersive Spectrometer (EDS) to know the m group and The ratio of the lanthanum element is about 0.6 to 1.0', preferably about 〇8 to 〇95. In one embodiment, when a copper sulfide-indium sulfide (CuS-Inj3) precursor film is deposited, wherein the steel/indium ratio is Approximately 0.93. In the prior art, a single layer of light absorbing layer is formed by chemical bath deposition. However, since the deposition speed of IB group ions (for example, copper ions) and mA group ions (such as indium ions) is different, two kinds of simultaneously When the chemical bath of the cation is deposited, the content of copper is significantly higher than that of indium or gallium, so that the photoelectric conversion efficiency of the light-collecting layer is not good. However, the present invention is respectively suitable for two kinds of gold. The deposition bath controls the ion concentration, temperature, pH value and deposition time of the bath respectively, not only can control the content of each layer, but also optimize the two different precursor films. After that, the precursor film is subjected to a heat treatment process. The heat treatment process includes a vacuum or non-vacuum heating process, which allows non-vacuum to be heated under an inert atmosphere, such as step 1〇3 or a gas containing a VIA element (eg, step 1〇4). The vulcanization process, the selenization process of step 〇5). Referring to step 103, the precursor film is subjected to a heat treatment process under an inert gas atmosphere to obtain a light absorbing layer, wherein the inert gas atmosphere includes: gas (N), gas (Η), nitrogen (Ar), Carbon monoxide (CO), a > vaporized nitrogen (NO) or a combination thereof. 201116648 Please refer to step 104, the precursor film is placed in hydrogen sulfide (h2S) or sulfur (S) vapor for heat treatment process, and in the step, the precursor film is placed in hydrogen selenide (H2Se) or selenium (Se) vapor. The heat treatment process is carried out. Finally, please refer to the dream 106. When the heat treatment process of step 103 or the vulcanization process of 104 is performed, a light absorbing layer of a ternary alloy such as copper indium sulfide can be obtained. With a small number of steps 107, when the selenization treatment of step 105 is carried out, a light absorbing layer of a quaternary alloy such as copper indium sulphide can be obtained.
因此，經由惰性氣體下之熱處理、硫化、砸化或是硫 φ 化、硒化兩者並行的熱處理，使1B_IIA族化合物與IIIA-VIA 族化合物交替疊層的前驅物薄膜進行相變化與晶體生長， 成為IB-IIIA-VIA族的光吸收層’其中光吸收層之厚度為 約 0.1 μιη~ 2 μιη。 上述熱處理步驟103、104與105之製程溫度為約300 。〇700。(：，較佳為約400°C〜600°C ’更佳為約430。(：〜530 X：，而熱處理製程之時間為約0.15小時〜10小時，較佳為 約0.3小時〜2小時’更佳為約〇.5小時〜1小時。 • 此處須注意的是’在進行熱處理時，由於IB_VIA族化 合物與IIIA-VIA族化合物交替疊層的結構，產生了 IB與 IIIA的濃度差（例如銅與銦之濃度差），當溫度高於相轉移 溫度時，會因為ΙΒ族與ΠΙΑ族從介面處的擴散行為，一 方面在介面處產生了 IB-IIIA_VIA的三相合金（例如銅銦 硫），另一方面會因為濃度差導致的擴散而促進了晶體生 長。本發明經由準確的控制1B-VIA族化合物（例如硫化銅) 與IIIA-VIA族化合物（例如硫化銦）的層數以及每—層的厚 度比例，則可控制前驅物溥膜内的整體的IB族MlA族之 201116648 元素比，進而影響熱處理後光吸收層内的IB族/VIA族之 元素比。一般認為IB族/VIA族之元素比（銅銦比）對於CIGS 太陽能電池十分重要，係因該比例決定了產生的光吸收層 是N-type還是P-type，而此光吸收層必須能與緩衝層形成 PN界面（P-N junction)才能產生所預期的光伏效應。 依本發明之製法所完成之光吸收層可將其應用於 CIGS電池上。請參見第2圖，如本領域人士所熟知，提供 一具有金屬電極之基板10，之後於此基板10上形成光吸 收層20，其中光吸收層包括IB-VIA族化合物21與. IIIA-VIA族化合物22，之後，再依序形成一緩衝層（buffer layer)30，一透明導電層（transparent conducting oxide，TCO) 40與一前電極50,即可完成一 CIGS太陽能電池。 上述之缓衝層30例如氫氧化銦(ln(〇H)3)、氫氧化鋅 (Zn(OH)2)、硫化錯(CdS)、氧化鋅(ZnO)、硫化鋅(ZnS)、砸 化銦（InxSey)、硫化銦(Ιηθ3)或上述之組合，其作用在於與 光吸收層20結合成為適當的異質接面(p_n juncti〇n)，其厚 度為約0.01 μιη〜0.5 μιη。上述之透明導電層（transparent conducting oxide, TCO) 40 例如氧化鋅：鋁（Zn〇:A1， alirniiimm doped zinc oxide，AZO)、氧化銦：錫（In2〇3:Sn)、 二氧化錫：氟(SnOyF)或上述之組合，其厚度為約〇」μιη〜i μιη。上述之前電極50例如鋁、銅、鎳或上述之組合，其 厚度為約0.1 μιη〜3 μιη。此外，尚可於透明導電層4〇之 上形成抗反射層60，此抗反射層6〇例如為氟化 或其它抗反射材料’其作用在於減少光7〇在入射過程中因 反射光產生而造成損耗。 201116648 依據上述製法製得之CIGS太陽能電池之光電轉換效 率（photo-electric conversion)為約 1·〇°/〇，於一實施例中，較 佳可達1.55 %。 綜上所述，本發明利用化學浴沉積法（CBD)製作光吸 收層’製程所需成本低且容易操作，而且可大面積化，未 來極具發展潛力。 • 【實施例】 實施例1·製備CuS薄膜 化學浴槽的配置：取0.8509克的CuCl2 (0.01 M)、1.9 克 SC(NH2)2(0.〇5 Μ)與 30.075 克單乙醇胺(MEA)(1M)溶於 500 ml之去離子水中。之後將化學浴槽pH值控制在114， 溫度控制在35°C，並持續以攪拌器充分攪拌。將基板放入 化學浴槽後，沉積40分鐘，之後，使用去離子水將表面沖 馨洗乾淨並烘乾，即可得到CuS薄膜(Cu/S元素比=〇.89/1)。 實施例2.製備In2s3薄膜 化學浴槽的配置：取1.1059克的InCl2 (〇.〇1 M)、1.875 克 sc(NH2)(CH3)(o.〇5 岣與 10.5〇7 克擰檬酸(citric acid) (〇·1 Μ)浴於500 ml之去離子水中。之後將化學浴槽值 控制在3.7，溫度控制在7〇°c，並持續以攪拌器充分攪拌。 將基板放入化學浴槽後，沉積丨.5小時，之後，使用去離 子水將表面沖洗乾淨並烘乾，即可得到In2S3薄膜(In/s元 素比= 1/1.4)。 201116648 實施例3.CIGS電池 光吸收層之製備：依據實施例 1與實施例2之步驟， 於鉬（Mo)基板之上依序沉積五層前驅物薄膜 ，各層結構與 沉積時間如下：CuS (25分鐘Hn2S3(1.5小時)-CuS(20分 鐘）-In2S3(1.5小時)_CuS(2〇分鐘）。之後將前驅物薄膜置於 充滿砸化氫氣體（Hje)之高溫爐内於54CTC下進行熱處理 (annealing)持溫20分鐘，以得到厚度為1〇93 8 nm之光吸 收層。 赢 之後於光吸收層之上依序形成硫化鎘（cdS)作為緩衝 層’形成氧化鋅：鋁（AZO)與氧化鋅(ZnO)作為透明導電 層’之後再形成金屬前電極’於此，即完成CIGS太陽能 電池。為了得知光吸收層的每個區域是否均勻成長，亦即 光吸收層的品質如何，本實施例將CIGS太陽能電池分割 成12個電池，如第3圖所示（圖中空白之處作為電極接觸 位置）。 表1顯示這12個小電池之效能表現，各數值如下：開 鲁 路電壓（open-circuit voltage，Voc)為 0.08 V 〜0.19 V、短路 電流（short-circuit current，Jsc)為 18.3 mA/cm2〜21.3 mA/cm2、填充因子（fill factor)為24 〇/〇〜35 %、光電轉換效 率（photo-electric conversion)為 0.168 % 〜1.55 %、並聯電 阻(shunt resistance，RSh)為 19 Ohm 〜166 Ohm、串聯電阻 (series resistance，Rs)為 19 Ohm 〜41 Ohm，其中並聯電阻 (Rsh)用於定義太陽能電池之漏電流大小，當並聯電阻越大 時，表示漏電流越小。另外，由表1得知目前最佳光電轉 12 201116648Therefore, the phase change and crystal growth of the precursor film in which the 1B_IIA compound and the IIIA-VIA compound are alternately laminated are subjected to heat treatment by heat treatment under an inert gas, vulcanization, deuteration or sulfur oxidization and selenization. , the light absorbing layer of the group IB-IIIA-VIA' wherein the light absorbing layer has a thickness of about 0.1 μm to 2 μm. The process temperatures of the above heat treatment steps 103, 104 and 105 are about 300. 〇700. (:, preferably about 400 ° C to 600 ° C 'more preferably about 430. (: ~ 530 X:, and the heat treatment process time is about 0.15 hours to 10 hours, preferably about 0.3 hours to 2 hours) 'More preferably, it is about 5 hours to 1 hour. ・ It should be noted here that the difference in concentration between IB and IIIA occurs due to the structure in which the IB_VIA compound and the IIIA-VIA compound are alternately laminated during the heat treatment. (For example, the difference in concentration between copper and indium), when the temperature is higher than the phase transition temperature, a three-phase alloy of IB-IIIA_VIA (for example, copper) is produced at the interface because of the diffusion behavior of the lanthanum and the lan from the interface. Indium sulfur), on the other hand, promotes crystal growth due to diffusion due to concentration differences. The present invention provides accurate control of the number of layers of Group 1B-VIA compounds (such as copper sulfide) and Group IIIA-VIA compounds (such as indium sulfide). And the thickness ratio of each layer can control the ratio of the elements of the Group IB family of MlA in the precursor film to the 201116648 element ratio, thereby affecting the element ratio of the Group IB/VIA group in the light absorbing layer after heat treatment. /VIA family element ratio (copper to indium ratio It is very important for CIGS solar cells because the ratio determines whether the resulting light absorbing layer is N-type or P-type, and the light absorbing layer must be able to form a PN junction with the buffer layer to produce the desired photovoltaic. The light absorbing layer completed by the method of the present invention can be applied to a CIGS battery. Referring to Figure 2, as is well known in the art, a substrate 10 having a metal electrode is provided, and thereafter on the substrate 10. Forming the light absorbing layer 20, wherein the light absorbing layer comprises the IB-VIA compound 21 and the IIIA-VIA compound 22, and then sequentially forming a buffer layer 30, a transparent conducting oxide (transparent conducting oxide, A COGS solar cell can be completed by TCO 40 and a front electrode 50. The above buffer layer 30 is, for example, indium hydroxide (ln(〇H)3), zinc hydroxide (Zn(OH)2), and vulcanization ( CdS), zinc oxide (ZnO), zinc sulfide (ZnS), indium antimonide (InxSey), indium sulfide (Ιηθ3) or a combination thereof, which functions to combine with the light absorbing layer 20 to form a suitable heterojunction (p_n juncti) 〇n), the thickness is about 0.01 μηη~0.5 μι η. The above transparent conducting oxide (TCO) 40 such as zinc oxide: aluminum (Zn〇: A1, alirniiimm doped zinc oxide, AZO), indium oxide: tin (In2〇3:Sn), tin dioxide: Fluorine (SnOyF) or a combination thereof, having a thickness of about 〇"μιη~i μιη. The front electrode 50 is, for example, aluminum, copper, nickel or a combination thereof, and has a thickness of about 0.1 μm to 3 μm. In addition, an anti-reflective layer 60 can be formed on the transparent conductive layer 4, which is, for example, a fluorinated or other anti-reflective material, which acts to reduce the generation of light 7 by the reflected light during the incident process. Causes loss. 201116648 The photo-electric conversion of a CIGS solar cell produced according to the above process is about 1·〇°/〇, and in one embodiment, preferably up to 1.55%. In summary, the process for producing a light absorbing layer by chemical bath deposition (CBD) is low in cost and easy to operate, and can be large in area, and has great potential for development in the future. • [Examples] Example 1: Preparation of CuS thin film chemical bath: 0.8509 g of CuCl2 (0.01 M), 1.9 g of SC(NH2)2 (0.〇5 Μ) and 30.075 g of monoethanolamine (MEA) ( 1M) Dissolved in 500 ml of deionized water. The pH of the chemical bath was then controlled at 114, the temperature was controlled at 35 ° C, and stirring was continued with a stirrer. After the substrate was placed in a chemical bath, it was deposited for 40 minutes. Thereafter, the surface was washed with deionized water and dried to obtain a CuS film (Cu/S element ratio = 〇.89/1). Example 2. Preparation of In2s3 thin film chemical bath: 1.1059 g of InCl2 (〇.〇1 M), 1.875 g of sc(NH2)(CH3) (o.〇5 岣 and 10.5〇7 g of citric acid) Acid) (〇·1 Μ) bath in 500 ml of deionized water, then control the chemical bath value to 3.7, control the temperature at 7 ° ° C, and continue to stir well with a stirrer. After placing the substrate in the chemical bath, After deposition for 5 hours, the surface of the In2S3 film was obtained by rinsing and drying the surface with deionized water (In/s element ratio = 1/1.4). 201116648 Example 3. Preparation of light absorption layer of CIGS battery: According to the steps of Example 1 and Example 2, five layers of precursor films were sequentially deposited on the molybdenum (Mo) substrate. The structure and deposition time of each layer were as follows: CuS (25 minutes Hn2S3 (1.5 hours) - CuS (20 minutes) -In2S3 (1.5 hours)_CuS (2 〇 minutes). The precursor film was then placed in a high-temperature furnace filled with hydrogen halide gas (Hje) and heat-treated at 54 CTC for 20 minutes to obtain a thickness of 1 〇93 8 nm light absorbing layer. After winning, cadmium sulfide (cdS) is formed sequentially on the light absorbing layer. The layer 'forms zinc oxide: aluminum (AZO) and zinc oxide (ZnO) as a transparent conductive layer' and then forms a metal front electrode', thereby completing the CIGS solar cell. In order to know whether each region of the light absorbing layer is uniformly grown That is, the quality of the light absorbing layer, this embodiment divides the CIGS solar cell into 12 batteries, as shown in Fig. 3 (the blank space in the figure serves as the electrode contact position). Table 1 shows the 12 small batteries. Performance, the values are as follows: open-circuit voltage (Voc) is 0.08 V ~ 0.19 V, short-circuit current (Jsc) is 18.3 mA / cm2 ~ 21.3 mA / cm2, fill factor ( Fill factor) is 24 〇 / 〇 ~ 35 %, photoelectric conversion efficiency (photo-electric conversion) is 0.168 % ~ 1.55 %, shunt resistance (RSh) is 19 Ohm ~ 166 Ohm, series resistance (series resistance, Rs ) is 19 Ohm ~ 41 Ohm, where the shunt resistance (Rsh) is used to define the leakage current of the solar cell. When the parallel resistance is larger, the leakage current is smaller. In addition, the best phototransistor 12 is known from Table 1. 2 01116648
化效率為約1.5%。The efficiency is about 1.5%.
實施例4.CIGS電池 光吸收層之製備：依據實施例1與實施例2之步驟 13 201116648 於鉬（Mo)基板之上依序沉積六層前驅物薄膜，各層結構與 沉積時間如下：CuS (15分鐘HnJ3 (1.5小時）_CuS (15分 鐘)-In2S3 (1.5 小時)-CuS (15 分鐘)-In2S3 (1.5 小時）。之後將 前驅物薄膜置於充滿硫化氫(H2S)氣體之高溫爐内於54〇t 下進行熱處理(annealing)持溫20分鐘，以得到厚度為約87〇 nm之光吸收層。 ’之後於光吸收層之上依序形成硫化鎘（CdS)作為缓衝 層，形成氧化鋅：鋁(AZO)與氧化鋅(ZnO)作為透明導電 層，之後再形成金屬前電極，於此，即完成CIGS太陽能 鲁 電池。為了得知光吸收層的每個區域是否均勻成長，亦即 光吸收層的品質如何，本實施例將CIGS太陽能電池分割 成12個電池，如第3圖所示。 表2顯示這12個小電池之效能表現，各數值如下：開 路電壓（open-circuit voltage，Voc)為 0.01 V- 0.22 V、短路 電流（short-circuit cunent，Jsc)為 5.9 mA/cm 〜15.5 mA/cm2、填充因子(fill factor)為24 %〜43 %、光電轉換效 率（photo-electric conversion)為 0.06 % ~ 1.3 %、並聯電阻 鲁 (shunt resistance，Rsh)為 2 Ohm 〜283 Ohm、串聯電阻（series resistance，Rs)為 2 Ohm 〜71 Ohm。 表2 電池 Voc Jsc FF 光 電 Rsh Rs (V) (mA/cm2) (%) 轉 化 (Ohm) (Ohm) 效 率 (°/〇) 201116648 電池1 0.18 12.860 34 0.810 198 71 電池2 0.16 13.727 33 0.709 141 62 電池3 0.00 8.719 _ 0.583 3 3 電池4 一 0.13 13.380 30 0.533 104 66 電池5 0.22 15.140 38 1.272 283 62 電池6 0.13 14.174 28 0.510 88 60 電池7 0.03 11.570 25 0.087 22 21 電池8 0.00 8.529 _ 0.311 4 4 電池9 0.00 5.876 一 1.060 2 2 電池10 0.18 14.702 32 0.853 152 68 電池11 0.01 12.033 43 0.060 8 8 電池12_ 0.08 15.455 21_ 0.360 49 41 註：由於切割電池時，電池3、8、9受到部分的損毀，因此電池之開 路電壓為0。Example 4. Preparation of Light Absorbing Layer of CIGS Battery: According to Example 1 and Step 13 of Example 2, 201116648, six layers of precursor films were sequentially deposited on a molybdenum (Mo) substrate. The structure and deposition time of each layer were as follows: CuS ( 15 minutes HnJ3 (1.5 hours) _CuS (15 minutes) - In2S3 (1.5 hours) - CuS (15 minutes) - In2S3 (1.5 hours). The precursor film is then placed in a high temperature furnace filled with hydrogen sulfide (H2S) gas. Annealing was carried out at 54 〇t for 20 minutes to obtain a light absorbing layer having a thickness of about 87 〇 nm. Then, cadmium sulfide (CdS) was sequentially formed as a buffer layer on the light absorbing layer to form an oxidation. Zinc: aluminum (AZO) and zinc oxide (ZnO) act as a transparent conductive layer, and then form a metal front electrode, thereby completing the CIGS solar cell. In order to know whether each region of the light absorbing layer is uniformly grown, that is, The quality of the light absorbing layer is different. In this embodiment, the CIGS solar cell is divided into 12 batteries, as shown in Fig. 3. Table 2 shows the performance of the 12 small batteries, and the values are as follows: open-circuit voltage , Voc) is 0.01 V- 0.22 V The short-circuit cunent (Jsc) is 5.9 mA/cm to 15.5 mA/cm2, the fill factor is 24% to 43%, and the photo-electric conversion is 0.06 % to 1.3%. The shunt resistance (Rsh) is 2 Ohm to 283 Ohm, and the series resistance (Rs) is 2 Ohm to 71 Ohm. Table 2 Battery Voc Jsc FF Photoelectric Rsh Rs (V) (mA/cm2) (% Conversion (Ohm) (Ohm) Efficiency (°/〇) 201116648 Battery 1 0.18 12.860 34 0.810 198 71 Battery 2 0.16 13.727 33 0.709 141 62 Battery 3 0.00 8.719 _ 0.583 3 3 Battery 4 A 0.13 13.380 30 0.533 104 66 Battery 5 0.22 15.140 38 1.272 283 62 Battery 6 0.13 14.174 28 0.510 88 60 Battery 7 0.03 11.570 25 0.087 22 21 Battery 8 0.00 8.529 _ 0.311 4 4 Battery 9 0.00 5.876 A 1.060 2 2 Battery 10 0.18 14.702 32 0.853 152 68 Battery 11 0.01 12.033 43 0.060 8 8 Battery 12_ 0.08 15.455 21_ 0.360 49 41 Note: Since the batteries 3, 8, and 9 are partially damaged when the battery is cut, the open circuit voltage of the battery is zero.
雖然本發明已以數個較佳實施例揭路如上，然其並非 用以限定本發明，任何所屬技術領域中具有通常知識者， 在不脫離本發明之精神和範圍内，當可作任意之動鱼 =本發明之保護範圍當視後附之申請專利範圍： 201116648 【圖式簡單說明】 第1圖為一流程圖，用以說明本發明光吸收層之製作 流程。 第2圖為一剖面圖，用以說明由本發明光吸收層所組 成之CIGS電池。 第3圖為一俯視圖，用以說明本發明實施例中電池之 分割示意圖。 【主要元件符號說明】 101〜提也一基板； 102〜以化學浴沉積法形成一前驅物薄膜於基板上； 102a〜形成IB-VIA族化合物； 102b〜形成IIIA-VIA族化合物； 103〜將前驅物薄膜置於惰性氣體氣氛中進行熱處理製 程； 104〜將前驅物薄膜進行硫化處理製程； 105〜將前驅物薄膜進行硒化處理製程； 106〜得到三元合金之光吸收層； 107〜得到四元合金之光吸收層； 10〜基板； 21〜IB-VIA族化合物； 22〜IIIA-VIA族化合物； 20〜光吸收層； 201116648While the present invention has been described above in terms of several preferred embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can be arbitrarily carried out without departing from the spirit and scope of the invention. The present invention is directed to the scope of the invention. Fig. 2 is a cross-sectional view for explaining a CIGS battery composed of the light absorbing layer of the present invention. Figure 3 is a plan view showing a schematic view of the division of the battery in the embodiment of the present invention. [Major component symbol description] 101~ mentioning a substrate; 102~ forming a precursor film on the substrate by chemical bath deposition; 102a~ forming an IB-VIA compound; 102b~ forming a IIIA-VIA compound; 103~ The precursor film is placed in an inert gas atmosphere for heat treatment; 104~ the precursor film is subjected to a vulcanization process; 105~ the precursor film is subjected to a selenization process; 106~ a ternary alloy light absorbing layer is obtained; Light absorbing layer of quaternary alloy; 10~substrate; 21~IB-VIA compound; 22~IIIA-VIA compound; 20~ light absorbing layer; 201116648
3 0〜缓衝層； 40〜透明導電層； 5 0〜如電極， 60〜抗反射層； 70〜光。3 0~buffer layer; 40~transparent conductive layer; 5 0~ as electrode, 60~ anti-reflective layer; 70~ light.