201032334 六、發明說明： 【發明所屬之技術領域】 本發明係種細太陽能電池及其製作方法，_是有關於 一種至少由具有i-m-VI族化合物形成之第—光吸收層與具有cias結 構之第二光吸收層堆疊組成之薄膜太陽能電池及其製作方法。 〇 【先前技術】201032334 VI. Description of the Invention: [Technical Field] The present invention relates to a thin solar cell and a method of fabricating the same, and relates to a first light absorbing layer formed of at least an im-VI compound and having a cias structure A thin film solar cell composed of a second light absorbing layer stack and a manufacturing method thereof. 〇 【Prior technology】
在習知技藝中，-般薄膜太陽能電池至少包含基板、前電極層、 光吸收層與背電極層，為了使細太陽能電池_較佳之光電轉換效 益，通常會至少由上光吸收層與下光吸收層之結構所組成，其中上光 吸收層具有η型料體層、i料諸層(本料)與p型料體層形成 之肿P接合面之非晶石夕，下光吸收層具有CIS(銅_)或cigs(銅銦嫁 硒)薄膜結狀彡晶則#滅前技狀美目專鄕6，卿92號已揭露 一種薄膜太陽能電池之結構1()，如第！圖所示，包含有依序叠層形成 之基板1卜背電極層12、具有CIS薄膜結構之下光吸收層ΐ3、η型導 體層I4、由Ρ型半導體層、i型半導體層说與η型半導體層⑺ 形成之非晶魏構之上光吸收層15以及前電極層Μ，藉由此上下兩組 先吸收層之堆疊結構，也就是CIS结構之彡晶石夕搭配η#接合面之非 晶妙’可提升此_太_電池1G對人射光譜的吸收關，然上述習 知技藝所縣的技術，雖可絲魏能雜圍增姉丨丨滅〜口別， 其光吸收層為CIS結構之多晶雜配n i_p接合面之非晶石夕的 二古其光魏_無法再增加，並且針對單—歧段的吸收係 、#二限制耻’如何找到適合能隙的材料來改善雜太陽能電 時努的魏進而達辦效率社陽能電池技術，仍是業界持 績努力探究的方向。 4 201032334 【發明内容】 為能更進-纽善絲驗的不足之處，本發贿供-種薄膜太 陽能電池，至少包含基板、背電極層、第一光吸收層、η型導體層、第 二光吸收層與前電極層依序堆#形成，其中此第__光吸收層係由 1-1腿方矣化合物所組成且此第一光吸收層具有第一能隙介於〇9與 1.2eV之間’而此第二光吸收層具有第—ρ型半導體薄膜、第二ρ型半 導趙薄膜與η型半導體薄膜以形成此第二光吸收層之ρ_ρ々之接合面且 此第二光吸收層具有第二能隙介於1>2與2 6eV之間 因此’本發明之主要目的在於提供一種薄膜太陽能電池，藉由第 -光吸收層與第二光魏層翻獨鎌之材料，可使_太陽能電 池之絲能隙範圍提升到L2eV〜2.6eV，藉由可吸收光波段的增加，據 此提高薄膜太陽能電之光電轉換效率。 因此，本發明之次要目的在於提供一種薄膜太陽能電池，藉由第 二光吸收層之結構具有p_p_nilp_n接合面’麟料__光波段的吸故 係數提高，特別可有效提高光波段為6〇〇〜124〇nm之光吸收係數至 10〜100倍。 因此，本發明之再一目的在於提供一種薄膜太陽能電池，藉由第 一光吸收層使用之族材料的不同，配合第二光吸收層與第三光 吸收層多層次的結構，使得本發明的變化組合更為彈性，可進一步調 整其能帶結構，達到更高的光電轉換效率。 因此，本發明之又一目的在於提供一種薄膜太陽能電池之製作方 法，其中第一光吸收層係由WII_VI族化合物形成與第二光吸收層具有 CIAS結構共同堆疊形成，大幅提高薄膜太陽能電池的光電轉換較率與 發電效率。 ' 因此本發明之又一目的在於提供一種薄膜太陽能電池之製作方 法’使用光吸收係數皆高於a_Si(如p_si，i_si，n_Si)之as材料，可增加 5 201032334 單一光波段的吸收係數， 提高整體薄膜太陽能電池的發電效率。 【實施方式】 尺寸完整繪製，盍先敘明 由於本發明係揭露-種薄膜太陽能電池及其製作方法，盆中所利 用的太光電轉·理，已馳術職具有通常知識者所能明 瞭’故以下文中之說明’不再作完整描述。同時，以下文中所對昭之 圖式，係表達與本發明特徵有關之結構示意，並未亦不需要_In the prior art, a thin film solar cell includes at least a substrate, a front electrode layer, a light absorbing layer and a back electrode layer. In order to make a thin solar cell _ better photoelectric conversion benefit, it is usually at least by the absorbing layer and the glazing layer. The structure of the absorbing layer, wherein the glazing absorbing layer has an n-type body layer, a layer of the material (the material) and a p-type body layer formed by the agglomerated P-joint surface, and the lower light absorbing layer has a CIS ( Copper _) or cigs (copper indium marry selenium) thin film 彡 则 则 # 灭 灭 灭 灭 灭 灭 灭 灭 灭 , , , , , , , , , , , , , , , , , , , , , , , , , The figure includes a substrate 1 formed by sequential lamination, a back electrode layer 12, a CIS film structure under the light absorbing layer ΐ3, an n-type conductor layer I4, a Ρ-type semiconductor layer, an i-type semiconductor layer, and η The amorphous semiconductor layer formed by the semiconductor layer (7) and the front electrode layer Μ, by the stacking structure of the upper and lower two first absorption layers, that is, the CIS structure of the twine eve with the η# joint surface Amorphous Miao' can enhance this _ too _ battery 1G absorption of the human emission spectrum, but the above-mentioned techniques of the art of the county, although the wire can be mixed with annihilation ~ mouth, its light absorption layer The crystals of the amorphous crystals of the polycrystalline miscellaneous n i_p junction of the CIS structure can no longer be increased, and how to find the material suitable for the energy gap for the absorption system of the single-dissection In order to improve the hybrid solar power, Wu, and the efficiency of the company's solar energy battery technology, is still the direction of the industry's efforts to explore. 4 201032334 [Summary of the Invention] In order to be able to further improve the shortcomings of New Zealand, the present invention provides a thin film solar cell comprising at least a substrate, a back electrode layer, a first light absorbing layer, an n-type conductor layer, and The second light absorbing layer and the front electrode layer are formed in sequence, wherein the first light absorbing layer is composed of a 1-1 leg square compound and the first light absorbing layer has a first energy gap between 〇9 and Between 1.2 eV' and the second light absorbing layer has a first-p type semiconductor film, a second p-type semiconductor film and an n-type semiconductor film to form a bonding surface of the second light absorbing layer ρ_ρ々 and this The second light absorbing layer has a second energy gap between 1 > 2 and 2 6 eV. Therefore, the main object of the present invention is to provide a thin film solar cell which is turned over by the first light absorbing layer and the second light absorbing layer. The material can increase the fiber gap range of the solar cell to L2eV~2.6eV, and increase the photoelectric conversion efficiency of the thin film solar power by increasing the absorbable light band. Therefore, a secondary object of the present invention is to provide a thin film solar cell in which the structure of the second light absorbing layer has a p_p_nilp_n junction surface, and the absorption coefficient of the optical band is increased, and the optical band is effectively increased by 6 〇〇. The light absorption coefficient of ~124〇nm is 10~100 times. Therefore, it is still another object of the present invention to provide a thin film solar cell which is combined with a multi-layer structure of a second light absorbing layer and a third light absorbing layer by using a different material of the first light absorbing layer. The combination of changes is more flexible, and the band structure can be further adjusted to achieve higher photoelectric conversion efficiency. Therefore, another object of the present invention is to provide a method for fabricating a thin film solar cell, wherein the first light absorbing layer is formed by a WII_VI compound and a second light absorbing layer having a CIAS structure, which greatly increases the photoelectricity of the thin film solar cell. Conversion rate and power generation efficiency. Therefore, another object of the present invention is to provide a method for fabricating a thin film solar cell using an as material having a light absorption coefficient higher than a_Si (e.g., p_si, i_si, n_Si), which can increase the absorption coefficient of a single light band of 5 201032334, and improve Power generation efficiency of monolithic thin film solar cells. [Embodiment] The dimensions are completely drawn, and the invention is disclosed. Since the invention discloses a thin film solar cell and a manufacturing method thereof, the photoelectric conversion used in the basin is the same as that of the general knowledge. Therefore, the description below will not be fully described. At the same time, the schematic diagrams in the following texts express the structural schematics related to the features of the present invention, and do not require _
請參考第2A圖，餘據本發明提出之第一較佳實施例，為一種薄 膜太陽能電池之賴，此薄膜太陽能電池：包含基板2卜背電極層η、 第-光吸收層23、η型導體層24、第二光吸收層25與前電極層％等 依序堆疊形成，其中此第-光吸收層23係由WII_VI族化合物所組成， 且此第一光吸收層23具有第一能隙介於〇 9與12eV之間，而第二光 吸收層25係由第-p型半導趙薄膜⑸、第型半導體薄膜Μ2與 η型半導體薄膜253所組成，據此形成p_p_n接合面之結構，並且第二 光吸收層25具有第二能隙介於i.2eV與2.6eV之間，其中第一 p型半 導體薄媒251與η型半導體薄膜253係選自結晶石夕、氣化非晶矽 (a-Si:H)、多晶矽(poly Si)、微晶石夕(μ-Si)、氫化非晶矽碳(a_Sic:H)或氫 化非晶石夕錯(a-SiGe:H)等其中一種，而第二p型半導體膜252係由 I-III-VI族化合物所組成。 在上述實施例中，第一光吸收層23之I-III-V1族化合物具有一化 學式.Cu (Ini.x，Gax) Se2 ’且X滿足條件.0 $X$ 0.6。上述第二光吸收_ 層25之第二p型半導體膜252之I-III-VI族化合物具有一化學式：Cu (Ιη^ΑΙχ) Ses ’且X滿足條件：0 S X S卜此外，I族元素可以是銅(Cu), ΙΠ族元素可以是鋁(A1)、銦(In)或鎵(Ga)，而VI族元素可以是硒(Se)或 硫(S)。此外’基板21的材質並不設限’可以是鋼、鐵、銘、銳、欽、 201032334 鉻、鉍或銻等其中一金屬材質，也可以是其他玻璃材質，如：鈉玻璃 (SLG)、鉀玻璃、鋁鎂玻璃、鉛玻璃、硼矽玻璃或石英玻璃等任一種。 前電極層26可以是二氧化錫(Sn〇2)、氧化銦錫(IT〇)、氧化鋅、 氧化銘鋅(AZO)、氧化鎵錫(GZO)或者是氧化銦鋅(izo)等其中—種，而 背電極層22可以是鉬、鋁、銀、鉑、鋅氧化物或是錫氧化物等任一種。 請參考第2B圖，係根據本發明提出之第二較佳實施例，為一種薄 膜太陽能電池之結構’此薄膜太陽能電池包含：基板21、背電極層22、 第一光吸收層23、η型導體層24、第二光吸收層25與前電極層％， 更進一步包含第一緩衝層271與第二緩衝層272，其中第一緩衝層271 係位於第二光吸收層25之第-ρ半導體薄膜2Μ與第二卩型半導體薄 膜252之間，而第二緩衝層272係位於第二光吸收層25之第二ρ型半 導逋薄膜252與η型半導體薄膜253之間，且第一緩衝層271與第二 緩衝層272之厚度介於1〇Α與5〇〇〇Α之間，其材質可以是由石夕碳化合 物(SiC)、矽鍺化合物(SiGe)或透明導電氧化物(TC〇)等其中一種，而本 實施例所用之基板21、背電極層22、第一光吸收層23、n型導體層24、 第二光吸收層25與前電極層26等材f、組成與能隙，相同於第一實 施例所述之。此外，第-緩衝層271與第二緩衝層272之形成方式可 以是《化學氣相_法、麵、真空驗法献學浴沉積法等 任一者。 請參考第3A圖，係根據本發明進一步所提出之第三較佳實施例， 為-種薄獻陽能電池之結構，此細太陽能電池包含基板Μ、背電 極層32、第-光吸收層33、n型導體層34、第二光吸收層^、第三光 吸收層37與前電極層36等依序堆疊形成，其中此第一光吸收層幻係 由I-III-VI族化合物所組成，且此第一光吸收層％具有第一能隙介於 〇.9eV與L2eV之間，而第二光吸收層35具有第二能隙為i⑽，第三 光吸收層37具有介κακίαν之間的第三能隙，其中第二光吸 201032334 收層35之結構與材質相同於第三光吸收層37，分別係由第—p型半導 體薄膜351、37卜第二p型半導體薄膜352、372與n型半導體薄膜 353、373所組成，據此形成具有p_p_n接合面之結構。此外，第—光吸 收層33與第二光吸收層35等所用之組成材質、結構與能隙，相同於 第-實施例所述之第-光吸收層23與第二光吸收層25。 另外，請參考第3B ® ’係根據本發明提出之第四較佳實施例，為 -種薄膜太陽能電池之結構’此薄臈太陽能電池包含：基板3卜背電 極層32、第-光吸收層33、n型導體層34、第二光吸收層％、第三光 吸收層37與前電極層36等，且可進一步包含第一、第二、第三及第 四緩衝層381、382、383、384，其中第一緩衝層381位在第二光吸收 層35之帛ρ型半導體薄膜351與第二卩型半導體薄膜之間，第 三緩衝層383位在第三光吸收層3?之第一 ρ型半導體薄膜奶與第二 Ρ型半導體薄膜372之間，而第二緩衝層382位在第二光吸收層％之 第-Ρ型半導趙薄膜352與η型半導體薄膜3幻之間，第四緩衝層384 則位在第三光吸收層37之第二ρ型半導體薄膜372與η型半導體薄膜 373之間’且這四種緩衝層38卜382、383、384之厚度係介於1〇人與 5000Α之間。而此薄膜太陽能電池3〇之基板31、背電極層％、第一 光吸收層33、η型導體層34、第二光吸收層％、前電極層％與第三 光吸收層37的組成材質、結構與能隙，皆相同如第三較佳實施例所述 之’而第一、第二、第三及第四緩衝層381、382、383、384之組成結 構與形成方相相同於第二較佳實_職之第一緩衝層 271或第二 緩衝層272。 &本發明再提出第五較佳實施例，請參考第4α圖，為一種薄膜太陽 月b電池40之結構，此薄膜太陽能電池*包含基板*卜背電極層π、 第光吸收層43、n型導體層44、第二光吸收層45與前電極層46依 序堆叠形成，其巾第—光吸㈣43係由ι·ιπ·νι族化合賴組成，且 8 201032334 此第一光吸收層43具有第一能隙介於0.9與l.2eV之間，而第二光吸 收層45係由一 P型半導體膜45丨與η型半導體薄膜452所組成，據此 形成ρ-η接合面結構，且第二光吸收層45具有第二能隙介於丨2eV與 2.6eV之間’其中p型半導體膜451係由wn_VI族化合物所組成而打 型半導體薄膜452可選自結晶矽、氫化非晶矽(a_ShH)、多晶矽 Si)、微晶石夕(μ-Si)、氫化非晶碎碳(a_sic:H)或氫化非晶石夕鍺(a-SiGe:H) 等其中一種。此外，基板41、背電極層42、第一光吸收層43、n型導 體層44以及前電極層46等組成材質、結構與能隙係相同於第一較佳 實施例所述之。 接著，請再參考第4B圖，係根據本發明提出之第六較佳實施例， 為一種薄膜太陽能電池之結構，此薄臈太陽能電池包含基板41、背電 極層42、第一光吸收層43、n型導體層44、第二光吸收層必與前電 極層46，且可進一步包含一緩衝層47，此緩衝層47位於第二光吸收 層45之P型半導體膜451與n型半導體薄膜452之間，在此要特別說 明的是，在此較佳實施例中，具有ρ_η接合面之光吸收層可以不只一 層，可根據實際狀況調整以達到最佳光電轉換較率，而在基板41、背 電極層42、第一光吸收層43、η型導體層44、第二光吸收層45與前 電極層46之組成材質、結構與能隙皆相同如第五較佳實施例所述，而 緩衝層47之組成結構與形成方式則相同於第二較佳實施例所述之第一 緩衝層271。 習知技術的光吸收層係由cis結構(意即WII_VI族化合物)之多晶 矽搭配n-i-p接合面之非晶矽，然相較於本發明所提出之上述實施例之 光吸收層之結構與組成，也就是由cis結構之多晶矽搭配具有pp_n或 是P-η接合面之光吸收層’使得本發明之吸光能隙範圍可以從習知的 1.4eV〜1.75eV提升到1.2eV~2.6eV ’不僅可調幅範圍更大，可吸收的光 波段也越廣泛’因此光電轉換效率亦可提高，且就材料的特性而言， 9 201032334 特別在常用全光波段(500nm〜1240nm)量測下，CIS系列之材料之光吸Referring to FIG. 2A, the first preferred embodiment of the present invention is a thin film solar cell comprising: a substrate 2, a back electrode layer η, a first light absorbing layer 23, and an n-type. The conductor layer 24, the second light absorbing layer 25 and the front electrode layer % are sequentially stacked, wherein the first light absorbing layer 23 is composed of a WII_VI compound, and the first light absorbing layer 23 has a first energy gap. Between 9 and 12 eV, and the second light absorbing layer 25 is composed of a p-p type semiconductor film (5), a first type semiconductor film 2 and an n type semiconductor film 253, thereby forming a structure of a p_p_n junction surface. And the second light absorbing layer 25 has a second energy gap between i.2eV and 2.6eV, wherein the first p-type semiconductor thin film 251 and the n-type semiconductor thin film 253 are selected from the group consisting of crystalline stone and vaporized amorphous矽(a-Si:H), polycrystalline germanium (poly Si), microcrystalline 夕 μ (μ-Si), hydrogenated amorphous 矽 carbon (a_Sic:H) or hydrogenated amorphous 夕 错 (a-SiGe:H) One of them, and the second p-type semiconductor film 252 is composed of a group I-III-VI compound. In the above embodiment, the I-III-V1 group compound of the first light absorbing layer 23 has a chemical formula of .Cu (Ini.x, Gax) Se2 ' and X satisfies the condition .0 $X$ 0.6. The I-III-VI compound of the second p-type semiconductor film 252 of the second light absorbing layer 25 has a chemical formula: Cu (Ιη^ΑΙχ) Ses ' and X satisfies the condition: 0 SXS Bu, in addition, the group I element can It is copper (Cu), the lanthanum element may be aluminum (A1), indium (In) or gallium (Ga), and the group VI element may be selenium (Se) or sulfur (S). In addition, the material of the substrate 21 is not limited to one of steel, iron, Ming, sharp, chin, 201032334 chrome, tantalum or niobium, or other glass materials such as soda glass (SLG). Any of potassium glass, aluminum-magnesium glass, lead glass, borosilicate glass or quartz glass. The front electrode layer 26 may be tin dioxide (Sn〇2), indium tin oxide (IT〇), zinc oxide, zinc oxide (AZO), gallium oxide (GZO) or indium zinc oxide (izo), among others— The back electrode layer 22 may be any one of molybdenum, aluminum, silver, platinum, zinc oxide or tin oxide. Please refer to FIG. 2B, which is a structure of a thin film solar cell according to a second preferred embodiment of the present invention. The thin film solar cell comprises: a substrate 21, a back electrode layer 22, a first light absorbing layer 23, and an n-type. The conductor layer 24, the second light absorbing layer 25 and the front electrode layer % further comprise a first buffer layer 271 and a second buffer layer 272, wherein the first buffer layer 271 is located at the first-th semiconductor of the second light absorbing layer 25. The second buffer layer 272 is located between the second p-type semiconductor film 252 and the n-type semiconductor film 253 of the second light absorbing layer 25, and the first buffer is between the second buffer layer 252 and the second semiconductor film 253. The thickness of the layer 271 and the second buffer layer 272 is between 1 〇Α and 5 ,, and the material thereof may be made of a stellite carbon compound (SiC), a bismuth compound (SiGe) or a transparent conductive oxide (TC). 〇) and the like, and the substrate 21, the back electrode layer 22, the first light absorbing layer 23, the n-type conductor layer 24, the second light absorbing layer 25, the front electrode layer 26, and the like used in the present embodiment are composed of f, composition and The energy gap is the same as that described in the first embodiment. Further, the first buffer layer 271 and the second buffer layer 272 may be formed by any one of a chemical vapor phase method, a surface, a vacuum test bath deposition method, or the like. Referring to FIG. 3A, a third preferred embodiment of the present invention is a thin solar cell comprising a substrate, a back electrode layer 32, a first light absorbing layer 33, and a thin solar cell. The n-type conductor layer 34, the second light absorbing layer, the third light absorbing layer 37 and the front electrode layer 36 are sequentially stacked, wherein the first light absorbing layer is composed of an I-III-VI compound. And the first light absorbing layer % has a first energy gap between 〇.9eV and L2eV, and the second light absorbing layer 35 has a second energy gap i(10), and the third light absorbing layer 37 has a medium κακίαν The third energy gap, wherein the second light absorption 201032334 layer 35 has the same structure and material as the third light absorbing layer 37, respectively, by the p-type semiconductor film 351, 37 and the second p-type semiconductor film 352, 372 and The n-type semiconductor films 353 and 373 are formed, whereby a structure having a p_p_n junction surface is formed. Further, the constituent materials, structures, and energy gaps of the first light absorbing layer 33, the second light absorbing layer 35, and the like are the same as those of the first light absorbing layer 23 and the second light absorbing layer 25 described in the first embodiment. In addition, please refer to the third preferred embodiment according to the present invention, which is a structure of a thin film solar cell. The thin solar cell comprises: a substrate 3, a back electrode layer 32, and a first light absorbing layer. 33, n-type conductor layer 34, second light absorbing layer%, third light absorbing layer 37 and front electrode layer 36, and the like, and may further include first, second, third and fourth buffer layers 381, 382, 383 384, wherein the first buffer layer 381 is located between the 帛ρ-type semiconductor film 351 and the second 卩-type semiconductor film of the second light absorbing layer 35, and the third buffer layer 383 is located at the third light absorbing layer 3 A p-type semiconductor film milk is interposed between the second germanium-type semiconductor film 372, and the second buffer layer 382 is located between the first-ply semiconductor film 352 and the n-type semiconductor film 3 of the second light absorbing layer. The fourth buffer layer 384 is located between the second p-type semiconductor film 372 and the n-type semiconductor film 373 of the third light absorbing layer 37 and the thickness of the four buffer layers 38 382, 383, 384 is between 1 〇 between 5,000 and Α. The constituent materials of the substrate 31, the back electrode layer %, the first light absorbing layer 33, the n-type conductor layer 34, the second light absorbing layer%, the front electrode layer%, and the third light absorbing layer 37 of the thin film solar cell 3〇 The structure and the energy gap are the same as described in the third preferred embodiment, and the constituent structures of the first, second, third, and fourth buffer layers 381, 382, 383, and 384 are the same as those of the forming phase. Secondly, the first buffer layer 271 or the second buffer layer 272 is used. The present invention further proposes a fifth preferred embodiment. Please refer to FIG. 4α, which is a structure of a thin film solar cell b. The thin film solar cell* includes a substrate, a back electrode layer π, a light absorbing layer 43, The n-type conductor layer 44, the second light absorbing layer 45 and the front electrode layer 46 are sequentially stacked, and the towel-light-absorbing (four) 43 is composed of the ι·ιπ·νι group, and 8 201032334 the first light absorbing layer 43 has a first energy gap between 0.9 and 1.2 eV, and the second light absorbing layer 45 is composed of a P-type semiconductor film 45 丨 and an n-type semiconductor film 452, thereby forming a ρ-η junction surface structure. And the second light absorbing layer 45 has a second energy gap between 丨2eV and 2.6eV' wherein the p-type semiconductor film 451 is composed of a wn_VI compound and the patterned semiconductor film 452 is selected from the group consisting of crystallization and hydrogenation. One of crystal germanium (a_ShH), polycrystalline germanium (Si), microcrystalline (μ-Si), hydrogenated amorphous carbon (a_sic: H) or hydrogenated amorphous a-SiGe (H). Further, the materials, structures, and energy gaps of the substrate 41, the back electrode layer 42, the first light absorbing layer 43, the n-type conductor layer 44, and the front electrode layer 46 are the same as those described in the first preferred embodiment. Next, referring to FIG. 4B, a sixth preferred embodiment of the present invention is a structure of a thin film solar cell including a substrate 41, a back electrode layer 42, and a first light absorbing layer 43. The n-type conductor layer 44, the second light absorbing layer and the front electrode layer 46, and further may include a buffer layer 47, the buffer layer 47 is located at the P-type semiconductor film 451 and the n-type semiconductor film of the second light absorbing layer 45. Between 452, it should be particularly noted that in the preferred embodiment, the light absorbing layer having the ρ_η bonding surface may have more than one layer, and may be adjusted according to actual conditions to achieve the best photoelectric conversion ratio, while on the substrate 41. The material, structure and energy gap of the back electrode layer 42, the first light absorbing layer 43, the n-type conductor layer 44, the second light absorbing layer 45 and the front electrode layer 46 are the same as described in the fifth preferred embodiment. The buffer layer 47 has the same structure and formation as the first buffer layer 271 described in the second preferred embodiment. The light absorbing layer of the prior art is composed of a polycrystalline germanium of a cis structure (that is, a WII_VI compound) and an amorphous germanium of a nip joint surface, which is comparable to the structure and composition of the light absorbing layer of the above-described embodiment of the present invention. That is, the polycrystalline germanium of the cis structure is combined with the light absorbing layer having a pp_n or P-η junction surface, so that the light absorption bandgap of the present invention can be increased from the conventional 1.4eV to 1.75eV to 1.2eV to 2.6eV. The amplitude modulation range is larger, and the absorbable light band is wider. Therefore, the photoelectric conversion efficiency can be improved, and in terms of material characteristics, 9 201032334 is particularly measured in the commonly used all-optical band (500 nm to 1240 nm), and the CIS series is used. Light absorption of materials
收係數皆高於a-Si(如p-Si，i-Si，n-Si)系列之材料，而p_CIAS即屬於CIS 同系列之材料，因此本發明提出具有{)_1)_11或1)_11接合面之光吸收層， 能夠將單一光波段的吸收係數提高，以600〜1240mn之光波段為例，本 發明的光吸收係數可比習知技術之p_Un結構之光吸收層高出1〇倍 〜100倍，並且，藉由Lm—vj族系列材料的使用彈性本發明的變化組 合較更為紐化，進_步調整其能騎構，達到更高的光電轉換效率。 ❹ 此外’本發明再提出第七較佳實施例，為一種薄膜太陽能電池之 製作方法，包含有 (1)提供一基板； ⑺形成-背電極層在基板上，其形成的方式不拘，以麟方式為較佳； 極層上— )，11¾導體層在第一光吸收層上，其中可以使用電聚增强化學氣 Z積^^)、減鍛法、真空蒸鍛法或是化學浴沉積法_)等 (:7:::;::':=一_上，成 恤㈣二辦 為較佳；以及 鑛法或者金屬有機化學蒸氣沉積法_CVD) 第二光吸收層之η型半_膜上。 及所達到的蝴如===所朗_與結構、以 201032334 々以上所述僅為本發明之較佳實施例，並非用以限定本發明之權利 範圍；同時以上的财’對於糊技術職之專卩认士應刊暸及實 施’因此其他未麟本發明賴*之精神下所完·*效改變或修 飾’均應包含在申請專利範圍中。 【圖式簡單說明】 第1圖為-剖面圖示意圖’為先前技術之薄媒太陽電池結構。 第2A圖為-剖面示意圖，係根據本發明提出之第一較佳實施例，為〜 種薄膜太陽能電池結構。 〜 第2B圖為-剖面不意圖，係根據本發明提出之第二較佳實施例，為〜 種薄膜太陽能電池結構。 〜 第3A圖為一剖面示意圖，係根據本發明提出之第三較佳實施例，為〜 種薄膜太陽能電池結構。 〜 第3B圖為-剖面示意圖’係根據本發明提出之第四較佳實施例，為〜 種薄膜太陽能電池結構。 第4A圖為-别面示意圖，係根據本發明提出之第五較佳實施例，為〜 種薄膜太陽能電池結構。 φ 第4B圖為一剖面示意圖’係根據本發明提出之第六較佳實施例，為〜 種薄膜太陽能電池結構。 【主要元件符號說明】 薄膜太陽能電池 1〇(先前技術） 基板 11(先前技術）、21、31、41 背電極層 12(先前技術）、22、32、42 下光吸收層 13(先前技術） η型導體層 14(先前技術）、24、34、44 上光吸收層 15(先前技術） 11 201032334 P型半導體層 151(先前技術） i型半導體層 152(先前技術） η型半導體層 153(先前技術） , 前電極層 16(先前技術）、26、36、46 第一光吸收層 23、33、43 第二光吸收層 25、35、45 第三光吸收層 37 第一Ρ型半導體薄膜 251 ' 351 ' 371 Α 第二Ρ型半導體薄膜 η型半導體薄膜 252、 352、372 253、 353、373、452 ρ型半導體膜 451 第一緩衝層 271 ' 381 第二緩衝層 272、382 第三緩衝層 383 第四緩衝層 384 緩衝層 47 12The collection coefficient is higher than that of a-Si (such as p-Si, i-Si, n-Si) series, and p_CIAS belongs to the same series of materials of CIS, so the invention proposes to have {)_1)_11 or 1)_11 The light absorbing layer of the joint surface can increase the absorption coefficient of a single optical band. Taking the optical band of 600 to 1240 nm as an example, the light absorption coefficient of the present invention can be 1 times higher than that of the p_Un structure of the prior art. 100 times, and by the use of the Lm-vj series of materials, the change combination of the present invention is more advanced, and the ride can be adjusted to achieve higher photoelectric conversion efficiency. Further, the present invention further provides a seventh preferred embodiment, which is a method for fabricating a thin film solar cell, comprising: (1) providing a substrate; (7) forming a back electrode layer on the substrate, the formation of which is not limited, The method is preferred; on the pole layer -), the 113⁄4 conductor layer is on the first light absorbing layer, wherein the electropolymerization enhanced chemical gas Z product can be used, the reduction forging method, the vacuum steaming method or the chemical bath deposition method _)etc. (:7:::;::':=一_上, 成 (4) 2 is better; and mining method or metal organic chemical vapor deposition method _CVD) n-type half of the second light absorbing layer _ Membrane. And the present invention is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; The special stipulations of the singers should be published and implemented. Therefore, the changes or modifications made by the other syllabuses should be included in the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a prior art thin-film solar cell structure. 2A is a cross-sectional view showing a thin film solar cell structure according to a first preferred embodiment of the present invention. ~ 2B is a cross-sectional view, not a schematic, and is a thin film solar cell structure according to a second preferred embodiment of the present invention. ~ Figure 3A is a schematic cross-sectional view showing a thin film solar cell structure according to a third preferred embodiment of the present invention. ~ Figure 3B is a cross-sectional view of a fourth preferred embodiment of the present invention, which is a thin film solar cell structure. Fig. 4A is a schematic view showing a thin film solar cell structure according to a fifth preferred embodiment of the present invention. φ Figure 4B is a schematic cross-sectional view showing a thin film solar cell structure according to a sixth preferred embodiment of the present invention. [Description of Main Element Symbols] Thin Film Solar Cell 1 (Prior Art) Substrate 11 (Prior Art), 21, 31, 41 Back Electrode Layer 12 (Prior Art), 22, 32, 42 Light Absorbing Layer 13 (Prior Art) N-type conductor layer 14 (prior art), 24, 34, 44 upper light absorbing layer 15 (prior art) 11 201032334 P-type semiconductor layer 151 (prior art) i-type semiconductor layer 152 (prior art) n-type semiconductor layer 153 ( Prior art), front electrode layer 16 (prior art), 26, 36, 46 first light absorbing layer 23, 33, 43 second light absorbing layer 25, 35, 45 third light absorbing layer 37 first Ρ type semiconductor film 251 ' 351 ' 371 Α second Ρ type semiconductor thin film n-type semiconductor film 252, 352, 372 253, 353, 373, 452 p-type semiconductor film 451 first buffer layer 271 ' 381 second buffer layer 272, 382 third buffer Layer 383 fourth buffer layer 384 buffer layer 47 12