201227997 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明涉及一種太陽能電池及其製備方法。 [0002] [0003] 【先前技術·】 太陽能係當今最清潔的能源之-，，孤…〜 。太陽能的利用方式包括光能-熱能轉換、光能_電能轉 換和光能_化學能轉換。太陽能電池係光能—電能轉換的 典型例子’係利用半導體材料的光生伏特原理製成的。 根據半導體光電轉換材料種類不同，太陽能電池可分為 矽基太陽能電池（請參見太陽能電池及多晶矽的生產材料與冶金學報，張明傑等，v〇16 , Ρ33-38 (2007))、 申化鎵太陽能電池、有機薄骐太陽能電池等。 太陽能電池財基太陽能電池為主。請參閱圖卜 先則技術中的太陽能電池4〇〇 ’該太陽能電池權包 取之不盡、用之不竭 背電極4Q、m底42、-摻_層44和 之_叱、上 099144862 電槌 — 挪7甩44和一上 有第—^片襯底42採用多或單晶碎製成，具 43，2面41""及與該第—表面41相對設置的第二表面 ―表面41歐_ ，且與_片襯底42的第 底42的第_表接觸。所述換雜石夕層以形成於所述石夕片襯“的4广43，作為光電轉換的材料。該摻㈣層 述检雜㈣“if平面結構二述上電極46設置於所 和摻雜發層“平成二边太知能電糊中石夕片概⑽ 產先複在㈣料教發下 奸)，所迷電子-空穴對在靜 A0I01 第4頁/共42頁 0992077455-0 201227997 [0004] Ο [0005] [0006] Ο 099144862 電勢能作許分心分別⑽ 動。如果在所述太陽At 電極40和上電極46移 端接上負載，就會〜4Q()的背電極40與上電極46兩 ，會有電流通過外電路中的負載。 然，先前技術中，士 , 咖妓* *於形成於所述㊉諸底42第二表面 43的摻雜矽層44 ^^ 表面為一平整的平面結構，其表面積 b 使所述太陽能電池400的取光面積較小。另外 太陽光線從外部入射到摻雜石夕層44的表面時，由於該 摻雜夕層44的表面為—平面結構，故照射到所述捧雜梦 :的光線°卩分被吸收，一部分被反射，而被反射的 光線不能再利用，故所述太陽能電池400對光線的利用率 較低。 ；' 【發明内容】 有鑒於此，提供一種具有較大取光面積的太陽能電池及 其製備方法實為必要。 一種太陽能電池，包括：一矽片襯底’所述矽片襯底具 有一第一表面以及與該第一表面相對設置的一第二表面 ’所述矽片襯底的第'二表面設置有複數個三維奈米結構 ，該三維奈米結構為階梯狀結構；一背電極，所述背電 極設置於所述矽片襯底的第〆表面，並與該第一表面歐 姆接觸；一摻雜矽層，所述摻雜矽層形成於所述三維奈 米結構的表面以及相鄰三維奈米結構之間的發片襯底的 第二表面；以及一上電極，所述上電極設置於所述摻雜 矽層的至少部分表面。 一種太陽能電池，包括從下炱上依次設置的—背電極， 一石夕片襯底，一捧雜石夕層，以及一上電極，其中，所述 表單編號A0101 第5頁/共42真 0 [0007] 201227997 ，^埤底靠近上電極的表面設置有複數個三維奈米結構 二认〜維奈米結構為階梯狀結構，所述摻雜矽層設置於 趣底Ί結構的表面以及相鄰三維奈米結構之間的石夕片 、的表面。 [0008] [0009] 所陽能電池的製備方法，包括：提供—石夕片概底， 置：夕片襯底具有一第-表面以及與該第-表面相對設 個⑽第二表面’所述W襯底的第二表面設置有複數 鄰三弟狀二維奈米結構；在所述三維奈米結構表面及相 ^維奈米結構之間的妙片襯廣的表面形成_摻雜碎層 ，提供 , 的至:、—上電極’並將所述上電極設置於所述摻雜石夕層 置^部分表面；以及提供—背電極，將所述背電極設 於所述發片襯底的第-表面，使所述背電極與所述石夕 片概底的第一表面歐姆接觸。 相較先前技術，所述太陽能電池通過在所述矽片襯底的 第二表面設置複數個階梯狀的三雄奈米結構，可提高所 述太陽能電池的取光面m，當域照射到所述三 維奈米結構的侧面時，該騎的光線―部分被吸收一部 分被反射，被反射的光線中大部分光線再—次入射至;目 鄰的二維奈米結構，被該相鄰的三維奈米結構吸收和反 射’故所述照射的光線在所述的三維奈米結構中發生複 數次反射及吸收，從而可進1提高所述太陽能電池對 光線的利用率。所述太陽能電池的製備方法該 藝簡單，成本低廉。 / 【實施方式】 下面將結合_及具體實施例，對本發明提供的太陽能 099144862 表單編號A0101 第6頁/共42頁 0992077455-0 [0010] 201227997 電$也作進-步的詳細說明。 [0011] ο [0012] G [0013] 099144862 5月參閱圖2，本發明第一實施例提佴〜 ，從下至上依次包括：―背電一種太陽能電池⑽ 推雜石夕層U以及—上電㈣。;^冗襯底12、-側入射。所述石夕片襯底12具有一第切所述上電極16--表面U相對設置的一第二表 表面11以及與該第 〜襯底12靠近所述上電極16的=第二表面13為 光切方向-側的表面第即表靠近太陽 置有複數個三維夺米缩5，兮*底的第-表面13設 狀結構.所述背雷搞， 〜轉奈米結構15為階梯 構，所以電極1Q設置於所料片襯底 並辑—表面u歐姆接觸;所述推㈣層脚 、所述一維奈米結構15的表面以及相鄰三維奈米結構 之間的破片襯底12的第二表面13 ;所述上電極i 6設置 於所述摻雜碎層14的至少部分表面。 所述背電極10的材料可為銘、錯或者銀等金屬。該背電 極10的厚度為10微米〜300微米。本實施例中，所述背電 極10為一厚度約為200微米的鋁箔。 凊參閱圖3，所述矽片襯底12為一p型矽片襯底，該p型矽 片襯底的材料可係單晶矽、多晶矽或其他的p型半導體材 料。本實施例中，所述矽片襯底12為一p型單晶矽片。所 述矽片襯底12的厚度為200微米〜300微米。所述矽片襯 底12第二表面13設置有複數個三維奈來結構15。該複數 個二維奈米結構15在所述石夕片襯底12上的第二表面13以 陣列形式設置。所述以陣列形式設置指所述複數個二維 奈米結構15可按照簡單立方排布、同心圓環排布或六角 第7頁/共42頁 表單編號A0101 201227997 形密堆排布等方式排列。而且，所述以陣列形式設置的 複數個三維奈米結構15可形成一個單一圖案或複數個圖 案。所述單一圖案可為三角形、平行四邊形、菱形、正 方形、矩形或圓形等。所述相鄰的兩個三維奈米結構1 5 之間的距離相等。所述相鄰的兩個三維奈米結構1 5之間 的距離為10奈米〜1 000奈米。所述複數個三維奈米結構 15在所述矽片襯底12上的第二表面13排列的形式以及相 鄰的兩個三維奈米結構1 5之間的距離可根據實際需要製 備。本實施例中，所述複數個三維奈米結構15呈六角形 密堆排布形成一單一正方形圖案，且相鄰兩個三維奈米 結構15之間的距離約為30奈米。 [0014] 該三維奈米結構15為階梯狀凸起結構。所述階梯狀凸起 結構為從所述矽片襯底12的第二表面13向外延伸出的階 梯狀突起的實體。所述階梯狀凸起結構為一複數層結構 ，如複數層三棱臺、複數層四棱臺、複數層六棱臺、複 數層圓柱或複數層圓臺等。本實施例中，所述階梯狀凸 起結構為複數層圓柱結構。所述階梯狀凸起結構的最大 尺寸為小於等於1 000奈米，即其長度、寬度和高度均小 於等於1 000奈米。優選地，所述階梯狀凸起結構的長度 、寬度和高度範圍為10奈米〜500奈米。 [0015] 請一併參閲圖4，本實施例中，所述三維奈米結構15為一 階梯狀凸起的雙層圓柱結構。具體地，所述三維奈米結 構15包括一第一圓柱152以及一設置於該第一圓柱152上 表面的第二圓柱154。所述第一圓柱152設置於所述矽片 襯底12的第二表面13，且所述第一圓柱152的側面垂直於 099144862 表單編號A0101 第8頁/共42頁 0992077455-0 201227997 矽片襯底12的第二表面〗3 ^所述第二圆柱154的側面垂直 於第一圓柱152的上表面。優選地，所述第一圓柱152與 第二圓柱154同軸設置，且該第一圓柱152與第二圓柱 154為一體結構，即所述第二圓柱154為第一圓柱152上 表面延伸出的圓柱狀結構。所述第一圓柱152的直徑大於 第二圓柱154的直徑。所述第一圓柱152的直徑為30奈米 〜1〇〇〇奈米，高度為50奈米〜1〇〇〇奈米。優選地所述第 一圓柱152的直徑為50奈米〜2〇〇奈米，高度為1〇〇奈米 5〇〇不米。所述第二圓柱154的直徑為1〇奈米奈米 ’高度為2〇奈米〜500奈米。優選地，所述第二圓柱i 54 的直徑為20奈米〜200奈米，高度為100奈米〜300奈米。 所述第-81柱152以及第二圓柱154的尺可根 要製備。本實施例中，所述第一圓柱152與第二= 同轴設置，且該第一圓柱152與第二圓柱154與所述碎片 襯幻2為-體結構。所述第一圓柱152的直徑為38〇奈米 ’高度為105奈米。所述第匕圓柱154的_為28〇奈米 ’高度為55奈米。 刚所述摻_層U形成於所述三維㈣結構15的表面以及 相鄰三維奈米結構15之間的矽片襯底以的第二表面Μ， 該摻雜石夕層U的材料為-N型摻雜石夕層。該換雜石夕層_ 通過向所述石夕片襯紐的第二表面13及設置於所財片 概底12的第二表面13上的複數個三維奈米結構15注入過 量的如磷或者坤等N型摻雜材料製備而成。所述N型摻雜 ^14的厚度為1()奈米]微米。所述摻雜㈣η與所述 片襯底12形成Ρ-Ν結結構，從而實現所述太陽能電池 099144862 表單編號Α0101 第9頁/共42頁 0992077455-0 201227997 1 00中光能到電能的轉換。可以理解，在所述矽片襯底1 2 的第二表面1 3設置複數個三維奈米結構1 5可使所述矽片 襯底12的第二表面13具有較大的Ρ-Ν結的界面面積，使所 述太陽能電池具有較大的取光面積；此外，所述複數個 三維奈米結構15具有光子晶體的特性，故，可增加光子 在所述三維奈米結構1 5的滯留時間以及所述三維奈米結 構15的吸收光的頻率範圍，從而提高所述太陽能電池100 的吸光效率，進而提高所述太陽能電池100的光電轉換效 率。 [0017] 另外，當光線照射到所述第一圓柱152與第二圓柱154的 側面時，該照射的光線一部分被吸收一部分被反射，被 反射的光線中大部分光線再一次入射至相鄰的三維奈米 結構15，被該相鄰的三維奈米結構15吸收和反射，故所 述照射的光線在所述的三維奈米結構15中發生複數次反 射及吸收，就係說，光線第一次照射到所述第一圓柱152 與第二圓柱15 4的側面時，被反射的光線大部分被再次利 用，從而可進一步提高所述太陽能電池100對光線的利用 率。 [0018] 所述上電極16可與所述摻雜矽層14部分接觸或完全接觸 。可以理解，所述上電極16可通過所述複數個三維奈米 結構15部分懸空設置，並與所述摻雜矽層14形成部分接 觸；所述上電極16亦可包覆於所述摻雜矽層14表面，並 與所述摻雜矽層14形成完全接觸。該上電極16可選自具 有良好的透光性能以及導電性能的銦錫氧化物結構及奈 米碳管結構，以使所述太陽能電池1 00具有較高的光電轉 099144862 表單編號Α0101 第10頁/共42頁 0992077455-0 201227997 [0019] Ο [0020] Ο [0021] 099144862 換政率、較好的耐用性以及均勻的電阻，從而提高所述 太陽能電池1 0 0的性能。 所述銦錫氧化物結構可係一氧化銦錫層，該銦錫氧化物 層可均勻地包覆於所述摻雜矽層14表面，並與所述摻雜 矽層14完全接觸。所述奈米碳管結構係由複數個奈米碳 ^組成的-個自支撐結構，該奈米碳管結構可為奈米碳 s膜或奈米碳管線，所述奈米碳管膜或奈米碳管線可通 過所述複數個三維奈米結構15部分懸空設置，並與所述 摻雜石夕層14形成部分接觸。輯自·結構係指該奈米 碳管結構可無需基底支撐，自支推存在。本實施例中， 所述上電極16為-奈米碳管旗，該奈米碳管膜係由複數 個奈米碳管組成的自支撐結構。該奈米碳管膜通過所述 旅數個二維奈米結構15部分懸空設置，並與所述摻雜矽 層14部分接觸’該奈米碳管膜用於收集所述Ρ-Ν結中通過 光能向電能轉換而產生的電流。 <以理解，所述太陽能電池100可進一步包括一本征隧道 層（圖中未不），該本征隧道層設置於所述矽片襯底12 及摻雜矽層14之間，該本征隧道層的材料為二氧化矽或 耆氬化矽。該本征隧道層的厚度為1埃〜30埃。所述本征 隧道層的設置可降低所述電子_空穴對在所述矽片襯底12 和摻雜矽層14接觸面的複合速度，從而進一步提高所述 木陽能電池100的光電轉換效率。 所述太陽能電池1〇〇中的矽片襯底12和摻雜矽層14的接觸 面形成有Ρ-Ν結。在接觸面上摻雜矽層14中的多餘電子趨 向矽片襯底12中的Ρ型矽片襯底，並形成一個由摻雜矽層 表單編號Α0101 第11頁/共42頁 0992077455-0 201227997 14指向石夕#襯底I2的内電場。太陽光從所述太陽能電池 100的上電極16〆側入射’當所述p_N結在太陽光的激發 下產生複數個電子_空穴對時，所述複數個電子—空穴對 在内電場作用下分離’ N型#雜材料中的電子向所述上電 極16移動，P—片概底中的空穴向所述背電極10移動， 然後分別被所述煮電極10和上電極16收集，形成電流。 [0022] [0023] [0024] 請參閱圖5，本發明進一步提供一種所述太陽能電池100 的製備方法，包括以下步褲：Sl〇，提供z矽片襯底，所 述矽片襯底具有〆第—表面IX及與該第〆表面相對設置 的一第二表面，所迷夕片麵*底的第二表面設置有複數個 階梯狀的三維奈米結構；su:，在所述彡維奈米結構表面 及相鄰三維奈米緒構之間的^襯底的第二表面形成〆 摻雜矽層；S12，提供一上電極，並將所述上電極設置於 所述摻雜矽層的炱少部分表面；S13，以及提供一背電極 ，將所述背電極設置於所、片襯底的第 一表面，使所 述背電極與所述矽片襯底的第—表面歐姆接觸。 ：.. ...... ... 請參閱圖6，所述步驟S10進〜步包括以下步驟： 步驟S101 ’提供i基板22 ’所述⑦基板22包括一第〆 表面21以及與該第-表面21相對設置的第二表面23。該 石夕基板22》P型♦片’該p型碎片的材料可係單晶石夕、 多晶碎或其他咐型半導體材料。本實施例中，所述石夕基 板22為一P型單晶發片。所述石夕基板22的厚度為2〇〇微來 .微米。所•基板22的大小、厚度和形狀不限，< 根據實際需要選擇。 099144862 表單編號A0101 第12頁/共42頁 0992077455Ό 201227997 [0025] 進一步，可對所述矽基板22的第二表面23進行親水處理 [0026] 首先，清洗所述矽基板22的第二表面23，清洗時採用超 淨間標準工藝清洗。然後，在溫度為30°C〜100°C，體積 比為NHg · Η^Ο . Η〗〇2 . HgO^x . y · z的溶液中溫浴30分 鐘~60分鐘，對所述矽基板22的第二表面23進行親水處理 ，之後用去離子水沖洗2次〜3次。其中，X的取值為 0.2〜2,7的取值為0.2~2,2的取值為1〜20。最後，用 氮氣對所述矽基板22的第二表面23進行吹幹。 [0027] 進一步，還可對所述矽基板22的第二表面23進行二次親 水處理，其具體包括以下步驟：將親水處理過後的所述 矽基板22在2wt%〜5wt%的十二烷基硫酸鈉溶液（SDS)中 浸泡2小時~24小時。可以理解，在SDS t浸泡過後的所述 矽基板22的第二表面23有利於後續奈米微球的鋪展並形 成有序排列的大面積奈米微球。 [0028] 步驟S102，在所述矽基板22的第二表面23形成掩膜層24 [0029] 所述在矽基板22的第二表面23形成掩膜層24的方法為在 所述矽基板22的第二表面23形成單層奈米微球。可以理 解，採用單層奈米微球作為掩膜層24，可在奈米微球對 應的位置製備得到階梯狀凸起結構。 [0030] 所述在矽基板22的第二表面23形成一單層奈米微球作為 掩膜層24具體包括以下步驟： [0031] 首先，製備一奈米微球的溶液。 第13頁/共42頁 0992077455-0 099144862 表單編號 A0101 201227997 闕本實施例中，在直徑為15楚米的表面皿中依次加入i5〇毫 升的純水、3微升〜5微升的〇. 〇lwt%〜1〇wt%的奈米微球 、以及當量的〇. lwt%~3wt%^SDS後形成混合物，將上述 混合物靜置分鐘30〜60分鐘。待奈米微球充分分散於混合 物中後，再加入1微升~3微升的41^%的汕5，以調節奈米 微球的表面張力，有利於形成單層奈米微球陣列。其中 ，奈米微球的直徑可為60奈米〜5〇〇奈米，具體地，'奈米 微球的直徑可為100奈米、2〇〇奈米、3〇〇奈米或4〇〇^米 ，上述直徑偏差為3奈米〜5奈来。優選的奈米微球的直 徑為2 0 0奈米或4 0 0奈米。^述奈米微球可為聚合物奈米 微球或矽奈米微球等。所述聚合物奈米微球的材料可為 聚苯乙烯（ps)或聚甲基丙烯酸甲酯（PMMA)。可以理解， 所述表面皿中的混合物可依實際需求而按比例調製。 [0033] 其次，在所述矽基板22的第二表面23形成一單層奈米微 球溶液，所述單層奈米微球以陣列形式設置於所述矽芙 板22的第二表面23。 " [0034] 採用提拉法或旋塗法在所述矽基板22的第二表面23形成 一單層奈米微球溶液。所述單層奈米微球可呈六角密堆 排布、簡單立方排布或同心圓環排布等。 [0035] 所述採用提拉法在矽基板22的第二表面23形成單層奈米 微球溶液的方法包括以下步驟：首先，將經親水處理後 的所述矽基板22緩慢的傾斜的沿著表面m的側壁滑入表 面jni的混合物中，所述矽基板22的傾斜角度為9。〜15。。 然後，將所述石夕基板2 2由表面皿_的混合物中緩慢的提起 0992077455-0 。其中，上述滑下和提起速度相當，均為5毫米/小時〜 099144862 表單煸號A0101 第14頁/共42頁 201227997 所述奈米微球的溶液中的奈米微 角毯、堆排布的單層奈米微球。 [0036] 毫米/小時《該過程中 球通過自組裝形成呈六 Ο 本實施例中，採用旋塗法切基板22的第二表面Μ形成 单層奈米微球溶液’其包如下步驟：首先，將親水處 理過後时基板22在2wt%的十二烧基硫酸输液中浸泡2 小時〜24小時’取出後在所述⑪基板22的第二表面23上塗 覆3微升~5微升的聚苯乙稀。其次，以旋塗轉速為糊轉/ 分鐘~500轉/分鐘的速度旋塗5秒~3〇秒。然後，以旋塗 轉速為800轉/分鐘]_轉/分鐘的速度旋謂秒〜2分鐘 後。再次，將旋塗轉速提高至1400轉/分鐘〜15〇〇轉/分 鐘，旋塗10秒〜20秒，除去邊緣多餘的微球。最後，將分 佈有奈米微球的第二表面23進行乾燥後即可在所述矽基 板22的第二表面23上形成呈六角密堆排布的單層奈米微 球，進而形成所述掩膜層24。此外’在形成所述掩膜層 24之後還可進一步對矽基板22的第二表面&進行烘烤。 G [0037] 所述烘烤的溫度為50。0~1〇〇。〇，烘烤的時間為丨分鐘~5 分鐘。 本實施例中，所述奈米微球的直徑可為4〇〇奈米。請參閱 圖7 ’所述單層奈綠球中的奈錢_能量最低的排布 方式排布，即六角密堆排布。所述單層奈米微球排布最 密集，佔空比最大。所述單層奈米微球中任意三個相鄰 的奈米微球呈一等邊三角形。 可以理解，通過控制奈米微球溶液的表面張力，可使單 層奈米微球中的奈米微球呈如圖8所示的簡單立方排布。 099144862 表單編號A0101 第15頁/共42頁 0992077455-0 [0038] 201227997 [0039]步驟S103，採用反應性蝕刻氣體26對所述矽基板22的第 二表面23進行蝕刻同時對所述掩膜層24進行腐蝕，在所 述矽基板22的第二表面23形成複數個階梯狀的三維奈米 結構25。 [0040] [0041] 所述採用反應性蝕刻氣體26對矽基板22的第二表面23進 行蝕刻的步驟在一微波等離子體系統中進行。所述微波 荨離子體系統為反應離子蚀刻（Reacti〇n_201227997 VI. Description of the Invention: [Technical Field of the Invention] [0001] The present invention relates to a solar cell and a method of fabricating the same. [0002] [Previous Technology] Solar energy is the cleanest energy source of today, -, .... Solar energy utilization includes light energy-thermal energy conversion, light energy_electric energy conversion, and light energy-chemical energy conversion. Solar cell light energy - a typical example of electrical energy conversion - is made using the photovoltaic principle of semiconductor materials. According to different types of semiconductor photoelectric conversion materials, solar cells can be classified into germanium-based solar cells (see Journal of Materials and Metallurgy, Journal of Metallurgy and Polycrystalline Silicon, Zhang Mingjie et al., v〇16, Ρ33-38 (2007)), Shenhua Gallium Solar Batteries, organic thin tan solar cells, etc. Solar cells are mainly based on solar cells. Please refer to the solar cell in the technology of Fig. 1 'The solar cell right package is inexhaustible, the inexhaustable back electrode 4Q, m bottom 42, - doped layer 44 and its _ 叱, on 099144862槌—Nove 7甩44 and a first substrate 42 are made of multiple or single crystal, having 43, 2 faces 41"" and a second surface-surface opposite the first surface 41 41 ohms _ and is in contact with the _ table of the bottom 42 of the _ sheet substrate 42. The replacement layer is formed on the slab of the stone lining "4, 43 as a material for photoelectric conversion. The doped (four) layer is quarantined (four) "if plane structure two upper electrode 46 is disposed in the Miscellaneous hair layer "Ping Cheng two sides can know the electric paste in the Shi Xi film summary (10) The first production in the (four) materials taught to send a rape), the electrons - hole pairs in the static A0I01 page 4 / a total of 42 pages 0992077455-0 201227997 [ 0004] Ο [0005] [0006] Ο 099144862 The potential can be distracted separately (10). If the load is connected to the sun At electrode 40 and the upper electrode 46, the back electrode 40 of ~4Q() The upper electrode 46 has a current flowing through the load in the external circuit. However, in the prior art, the surface of the doped germanium layer 44 formed on the second surface 43 of the ten bottoms 42 is A flat planar structure having a surface area b such that the light extraction area of the solar cell 400 is small. Further, when the solar light is incident from the outside onto the surface of the doped layer 44, since the surface of the doped layer 44 is - The plane structure, so the light that is irradiated to the dream: the light is absorbed, part of it is reflected, and is reflected The line cannot be reused, so the utilization rate of the light of the solar cell 400 is low. [Invention] In view of the above, it is necessary to provide a solar cell having a large light extraction area and a preparation method thereof. a battery comprising: a cymbal substrate having a first surface and a second surface disposed opposite the first surface; the second surface of the cymbal substrate is provided with a plurality of a three-dimensional nanostructure, the three-dimensional nanostructure is a stepped structure; a back electrode, the back electrode is disposed on the second surface of the enamel substrate, and is in ohmic contact with the first surface; The doped germanium layer is formed on a surface of the three-dimensional nanostructure and a second surface of the hairspring substrate between adjacent three-dimensional nanostructures; and an upper electrode, the upper electrode being disposed on the blend At least part of the surface of the hybrid layer. A solar cell comprising a back electrode disposed in sequence from the lower jaw, a stone substrate, a heterogeneous layer, and an upper electrode, wherein the form number A0101 5 Page / a total of 42 true 0 [0007] 201227997, ^ bottom is close to the surface of the upper electrode is provided with a plurality of three-dimensional nanostructures two-vehicle structure is a stepped structure, the doped layer is placed at the bottom of the fun The surface of the structure and the surface of the stone cube between the adjacent three-dimensional nanostructures. [0008] [0009] The preparation method of the solar cell includes: providing a stone substrate, placing: a substrate Having a first surface and a second surface opposite to the first surface, the second surface of the W substrate is provided with a plurality of adjacent three-dimensional two-dimensional nanostructures; on the surface of the three-dimensional nanostructure and The surface of the smectic lining between the phase-Vinite structures forms a _ doped layer, providing, to: the upper electrode and placing the upper electrode on the doped layer And providing a back electrode, the back electrode being disposed on a first surface of the hair piece substrate, such that the back electrode is in ohmic contact with the first surface of the stone substrate. Compared with the prior art, the solar cell can increase the light-receiving surface m of the solar cell by providing a plurality of stepped three male nano structures on the second surface of the cymbal substrate. When the side of the three-dimensional nanostructure is used, the light of the ride is partially absorbed and partially reflected, and most of the reflected light is incident again; the two-dimensional nanostructure of the neighbor is the adjacent three-dimensional The structure absorbs and reflects, so that the irradiated light is reflected and absorbed in the three-dimensional nanostructure in a plurality of times, so that the utilization of light by the solar cell can be improved. The method for preparing the solar cell is simple in the art and low in cost. [Embodiment] Hereinafter, the solar energy provided by the present invention will be described in conjunction with the specific embodiment. 099144862 Form No. A0101 Page 6 of 42 0992077455-0 [0010] 201227997 The electricity $ is also described in detail. [0012] [0012] G [0013] G [0013] 099144862 May, referring to FIG. 2, the first embodiment of the present invention provides a 佴~, from bottom to top, including: - back-up a solar cell (10) pushes the stone layer U and - on Electricity (four). ; ^ redundant substrate 12, - side incidence. The slab substrate 12 has a second surface 13 on which the upper electrode 16 is disposed opposite to the surface U and a second surface 13 adjacent to the upper electrode 16 of the first substrate 12. For the direction of the light-cutting side, the surface is close to the sun, and there are a plurality of three-dimensional squash, and the first surface 13 of the 兮* bottom is shaped. The back is made up, and the nano-structure 15 is a stepped structure. Therefore, the electrode 1Q is disposed on the substrate substrate and the surface-u ohmic contact; the push (four) layer leg, the surface of the one-dimensional nanostructure 15 and the fragment substrate 12 between the adjacent three-dimensional nanostructures a second surface 13; the upper electrode i6 is disposed on at least a portion of the surface of the doped layer 14. The material of the back electrode 10 may be metal such as imprint, error or silver. The back electrode 10 has a thickness of 10 μm to 300 μm. In this embodiment, the back electrode 10 is an aluminum foil having a thickness of about 200 μm. Referring to Figure 3, the cymbal substrate 12 is a p-type ruthenium substrate, and the material of the p-type ruthenium substrate can be a single crystal germanium, polysilicon or other p-type semiconductor material. In this embodiment, the cymbal substrate 12 is a p-type single crystal cymbal. The ruthenium substrate 12 has a thickness of from 200 μm to 300 μm. The second surface 13 of the cymbal substrate 12 is provided with a plurality of three-dimensional nanostructures 15. The plurality of two-dimensional nanostructures 15 are disposed in an array on the second surface 13 of the slab substrate 12. The arrangement in the form of an array means that the plurality of two-dimensional nanostructures 15 can be arranged according to a simple cubic arrangement, a concentric annular arrangement or a hexagonal page 7/42 page form number A0101 201227997. . Moreover, the plurality of three-dimensional nanostructures 15 arranged in an array form a single pattern or a plurality of patterns. The single pattern may be a triangle, a parallelogram, a diamond, a square, a rectangle, or a circle. The distance between the adjacent two three-dimensional nanostructures 15 is equal. The distance between the adjacent two three-dimensional nanostructures 15 is from 10 nm to 1 000 nm. The form in which the plurality of three-dimensional nanostructures 15 are arranged on the second surface 13 of the cymbal substrate 12 and the distance between two adjacent three-dimensional nanostructures 15 can be prepared according to actual needs. In this embodiment, the plurality of three-dimensional nanostructures 15 are arranged in a hexagonal dense cell to form a single square pattern, and the distance between two adjacent three-dimensional nanostructures 15 is about 30 nm. [0014] The three-dimensional nanostructure 15 is a stepped convex structure. The stepped raised structure is an entity of stepped protrusions that extend outwardly from the second surface 13 of the cymbal substrate 12. The stepped protrusion structure is a plurality of layer structures, such as a plurality of layers of triangular prisms, a plurality of layers of quadrangular prisms, a plurality of layers of hexagonal prisms, a plurality of layers of cylinders or a plurality of layers of circular tables. In this embodiment, the stepped convex structure is a plurality of layered cylindrical structures. The stepped projection structure has a maximum dimension of less than or equal to 1,000 nanometers, i.e., its length, width, and height are less than or equal to 1,000 nanometers. Preferably, the stepped projection structure has a length, a width and a height ranging from 10 nm to 500 nm. [0015] Referring to FIG. 4 together, in the embodiment, the three-dimensional nanostructure 15 is a double-layered cylindrical structure with a stepped protrusion. Specifically, the three-dimensional nanostructure 15 includes a first cylinder 152 and a second cylinder 154 disposed on an upper surface of the first cylinder 152. The first cylinder 152 is disposed on the second surface 13 of the cymbal substrate 12, and the side surface of the first cylinder 152 is perpendicular to 099144862. Form No. A0101 Page 8 / Total 42 Page 0992077455-0 201227997 lining The second surface of the bottom 12 is 3 ^ The side of the second cylinder 154 is perpendicular to the upper surface of the first cylinder 152. Preferably, the first cylinder 152 is coaxial with the second cylinder 154, and the first cylinder 152 and the second cylinder 154 are a unitary structure, that is, the second cylinder 154 is a cylinder extending from the upper surface of the first cylinder 152. Structure. The diameter of the first cylinder 152 is greater than the diameter of the second cylinder 154. The first cylinder 152 has a diameter of 30 nm to 1 〇〇〇 nanometer and a height of 50 nm to 1 〇〇〇 nanometer. Preferably, the first cylinder 152 has a diameter of 50 nm to 2 Å nanometers and a height of 1 〇〇 nanometer 5 〇〇 not meters. The second cylinder 154 has a diameter of 1 nanometer nanometer and a height of 2 nanometers to 500 nanometers. Preferably, the second cylinder i 54 has a diameter of 20 nm to 200 nm and a height of 100 nm to 300 nm. The dimensions of the -81th column 152 and the second cylinder 154 can be prepared. In this embodiment, the first cylinder 152 is disposed coaxially with the second ==, and the first cylinder 152 and the second cylinder 154 and the fragment lining 2 are a body structure. The first cylinder 152 has a diameter of 38 nanometers and a height of 105 nanometers. The 匕 cylinder 154 has a _ of 28 〇 nanometer height of 55 nm. Immediately after the doping layer U is formed on the surface of the three-dimensional (four) structure 15 and the second surface layer of the wafer substrate between the adjacent three-dimensional nanostructures 15, the material of the doped layer U is - N-type doped stone layer. The replacement layer is injected with an excess of phosphorus such as phosphorus or a plurality of three-dimensional nanostructures 15 disposed on the second surface 13 of the stone substrate and the second surface 13 of the substrate 12 Kun and other N-type doping materials are prepared. The thickness of the N-type dopant ^14 is 1 () nm] μm. The doping (tetra) η forms a Ρ-Ν junction structure with the sheet substrate 12, thereby realizing the conversion of light energy to electric energy in the solar cell 099144862 Form No. Α0101 Page 9 / Total 42 page 0992077455-0 201227997 1 00. It can be understood that a plurality of three-dimensional nanostructures 15 are disposed on the second surface 13 of the cymbal substrate 12 to make the second surface 13 of the cymbal substrate 12 have a larger Ρ-Ν junction. The interface area is such that the solar cell has a larger light extraction area; in addition, the plurality of three-dimensional nanostructures 15 have the characteristics of a photonic crystal, so that the residence time of the photon in the three-dimensional nanostructure 15 can be increased. And a frequency range of the light absorption of the three-dimensional nanostructure 15, thereby increasing the light absorption efficiency of the solar cell 100, thereby improving the photoelectric conversion efficiency of the solar cell 100. [0017] In addition, when light is irradiated to the side surfaces of the first cylinder 152 and the second cylinder 154, a part of the irradiated light is partially absorbed and reflected, and most of the reflected light is once again incident to the adjacent one. The three-dimensional nanostructure 15 is absorbed and reflected by the adjacent three-dimensional nanostructure 15 , so that the irradiated light is reflected and absorbed in the three-dimensional nanostructure 15 in multiple times, that is, the light is first When the first cylinder 152 and the side of the second cylinder 154 are irradiated to the side, the reflected light is mostly reused, so that the utilization of light by the solar cell 100 can be further improved. [0018] The upper electrode 16 may be in partial or full contact with the doped germanium layer 14. It can be understood that the upper electrode 16 can be partially suspended by the plurality of three-dimensional nanostructures 15 and partially contacted with the doped germanium layer 14; the upper electrode 16 can also be coated with the doping. The surface of the germanium layer 14 is in complete contact with the doped germanium layer 14. The upper electrode 16 may be selected from an indium tin oxide structure and a carbon nanotube structure having good light transmission properties and electrical conductivity so that the solar cell 100 has a high photoelectric conversion 099144862 Form No. Α0101 Page 10 / Total 42 pages 0992077455-0 201227997 [0019] 002 [0021] 099144862 The power exchange rate, better durability and uniform resistance, thereby improving the performance of the solar cell 100. The indium tin oxide structure may be an indium tin oxide layer which is uniformly coated on the surface of the doped germanium layer 14 and is in complete contact with the doped germanium layer 14. The carbon nanotube structure is a self-supporting structure composed of a plurality of nano carbon tubes, and the carbon nanotube structure may be a nano carbon s film or a nano carbon line, or the carbon nanotube film or The nano carbon pipeline may be partially suspended by the plurality of three-dimensional nanostructures 15 and partially contacted with the doped layer 14 . The series structure means that the carbon nanotube structure can be self-supporting without the need of a substrate support. In this embodiment, the upper electrode 16 is a carbon nanotube flag, and the carbon nanotube film is a self-supporting structure composed of a plurality of carbon nanotubes. The carbon nanotube film is suspended by a portion of the two-dimensional nanostructure 15 and is in contact with the doped germanium layer 14. The carbon nanotube film is used to collect the tantalum-niobium junction. The current generated by the conversion of light energy to electrical energy. <Understanding, the solar cell 100 may further include an intrinsic tunnel layer (not shown) disposed between the enamel substrate 12 and the doped yttrium layer 14, the present The material of the tunnel layer is cerium oxide or cerium argon. The intrinsic tunnel layer has a thickness of 1 angstrom to 30 angstroms. The arrangement of the intrinsic tunnel layer can reduce the recombination speed of the electron-hole pair on the contact surface of the enamel substrate 12 and the doped yttrium layer 14, thereby further improving the photoelectric conversion of the yang solar cell 100. effectiveness. The contact surface of the ruthenium substrate 12 and the doped ruthenium layer 14 in the solar cell 1 is formed with a Ρ-Ν junction. The excess electrons in the doped germanium layer 14 on the contact surface tend to the germanium type germanium substrate in the germanium substrate 12, and form a doped germanium layer form number Α0101 page 11/total 42 page 0992077455-0 201227997 14 points to the internal electric field of Shi Xi # substrate I2. Sunlight is incident from the side of the upper electrode 16 of the solar cell 100. When the p_N junction generates a plurality of electron-hole pairs under the excitation of sunlight, the plurality of electron-hole pairs act on the internal electric field. The electrons in the lower separation 'N-type # impurity material are moved toward the upper electrode 16, and the holes in the P-sheet are moved toward the back electrode 10, and then collected by the boiling electrode 10 and the upper electrode 16, respectively. Forming a current. [0024] Referring to FIG. 5, the present invention further provides a method for fabricating the solar cell 100, comprising the following steps: S1, providing a z-substrate substrate, the cymbal substrate having a first surface IX and a second surface opposite to the surface of the second surface, the second surface of the bottom surface is provided with a plurality of stepped three-dimensional nanostructures; su: Forming an erbium-doped ruthenium layer on the surface of the nanostructure and the second surface of the adjacent three-dimensional nanostructure; S12, providing an upper electrode, and disposing the upper electrode on the doped ruthenium layer And reducing a portion of the surface; S13, and providing a back electrode, the back electrode is disposed on the first surface of the substrate, such that the back electrode is in ohmic contact with the first surface of the enamel substrate. Referring to FIG. 6, the step S10 further includes the following steps: Step S101 'Providing the i substrate 22' The 7 substrate 22 includes a second surface 21 and The second surface 23 of the first surface 21 is oppositely disposed. The material of the p-type chip can be a single crystal, polycrystalline or other germanium-type semiconductor material. In this embodiment, the stone base plate 22 is a P-type single crystal hair piece. The thickness of the stone substrate 22 is 2 micrometers. The size, thickness, and shape of the substrate 22 are not limited, and are selected according to actual needs. 099144862 Form No. A0101 Page 12 / Total 42 Page 0992077455 Ό 201227997 [0025] Further, the second surface 23 of the ruthenium substrate 22 may be subjected to a hydrophilic treatment [0026] First, the second surface 23 of the ruthenium substrate 22 is cleaned, Cleaning is carried out using a clean process in a clean room. Then, at a temperature of 30 ° C to 100 ° C, the volume ratio is NHg · Η ^ Ο Η 〇 . 2 HgO ^ x y · z solution in a bath for 30 minutes to 60 minutes, the ruthenium substrate The second surface 23 of 22 is subjected to a hydrophilic treatment, followed by rinsing 2 times to 3 times with deionized water. Wherein, the value of X is 0.2 to 2, the value of 7 is 0.2 to 2, and the value of 2 is 1 to 20. Finally, the second surface 23 of the tantalum substrate 22 is blown dry with nitrogen. [0027] Further, the second surface 23 of the ruthenium substrate 22 may be subjected to a second hydrophilic treatment, which specifically includes the following steps: the hydrophilically treated ruthenium substrate 22 is at 2 wt% to 5 wt% of dodecane Soak in sodium sulphate solution (SDS) for 2 hours to 24 hours. It will be appreciated that the second surface 23 of the tantalum substrate 22 after SDS t soaking facilitates the spreading of subsequent nanospheres and forms an ordered array of large area nanospheres. [0028] Step S102, forming a mask layer 24 on the second surface 23 of the germanium substrate 22 [0029] The method of forming the mask layer 24 on the second surface 23 of the germanium substrate 22 is at the germanium substrate 22 The second surface 23 forms a single layer of nanospheres. It can be understood that a single layer of nanospheres is used as the mask layer 24, and a stepped convex structure can be prepared at a position corresponding to the nanospheres. [0030] The forming of a single layer of nanospheres as the mask layer 24 on the second surface 23 of the ruthenium substrate 22 specifically includes the following steps: [0031] First, a solution of a nanosphere is prepared. Page 13 of 42 0992077455-0 099144862 Form No. A0101 201227997 In this example, i5〇 ml of pure water and 3 μl to 5 μl of 〇 are sequentially added to a watch glass with a diameter of 15 cm. 〇1wt%~1〇wt% of the nanospheres, and an equivalent amount of 〇. lwt%~3wt%^SDS form a mixture, and the mixture is allowed to stand for 30 to 60 minutes. After the nanospheres are fully dispersed in the mixture, 1 μl to 3 μl of 41% 汕5 is added to adjust the surface tension of the nanospheres, which is favorable for forming a single layer of nanosphere arrays. Wherein, the diameter of the nanospheres may be from 60 nanometers to 5 nanometers, and specifically, the diameter of the nanospheres may be 100 nanometers, 2 nanometers, 3 nanometers or 4 inches. 〇^米, the above diameter deviation is 3 nm ~ 5 Nai. Preferred nanospheres have a diameter of 200 nm or 400 nm. The nai microspheres may be polymer nanospheres or nanometer microspheres. The material of the polymer nanospheres may be polystyrene (ps) or polymethyl methacrylate (PMMA). It will be appreciated that the mixture in the watch glass can be scaled as needed. [0033] Next, a single layer of nanosphere solution is formed on the second surface 23 of the ruthenium substrate 22, and the single layer of nanospheres is disposed in an array on the second surface 23 of the raft plate 22. . " [0034] A single layer of nanosphere solution is formed on the second surface 23 of the ruthenium substrate 22 by a pulling or spin coating method. The single-layer nano microspheres may be arranged in a hexagonal close-packed arrangement, a simple cubic arrangement or a concentric annular arrangement. [0035] The method for forming a single-layer nanosphere solution on the second surface 23 of the ruthenium substrate 22 by the pulling method comprises the following steps: First, the hydrophilically treated ruthenium substrate 22 is slowly tilted along the edge The side wall of the surface m is slid into the mixture of the surface jni, which has an inclination angle of 9. ~15. . Then, the stone substrate 2 2 is slowly lifted from the mixture of the watch glass to 0992077455-0. Among them, the above-mentioned sliding down and lifting speed are equivalent, both are 5 mm / h ~ 099144862 Form No. A0101 Page 14 / Total 42 pages 201227997 The nano micro-angle blanket in the solution of the nano microspheres, the stack of cloth Single layer nanospheres. [0036] mm/hr "The ball is formed by self-assembly in the process. In this embodiment, the second surface of the substrate 22 is formed by spin coating to form a single-layer nano-microsphere solution." The package is as follows: After the hydrophilic treatment, the substrate 22 is immersed in a 2 wt% dodecaine sulfuric acid infusion for 2 hours to 24 hours. After the extraction, 3 microliters to 5 microliters of the poly layer is coated on the second surface 23 of the 11 substrate 22. Phenylethylene. Next, spin-coat at a speed of paste rotation/minute to 500 rpm for 5 seconds to 3 seconds. Then, at a speed of 800 rpm, the speed of spin-coating is rpm/min. Again, the spin coating speed was increased to 1400 rpm to 15 rpm/min, and spin coating was applied for 10 seconds to 20 seconds to remove excess microspheres at the edges. Finally, the second surface 23 on which the nanospheres are distributed is dried to form a single layer of nanospheres arranged in a hexagonal close-packed manner on the second surface 23 of the base substrate 22, thereby forming the Mask layer 24. Further, the second surface & of the ruthenium substrate 22 may be further baked after the formation of the mask layer 24. G [0037] The baking temperature is 50. 0~1〇〇. Oh, the baking time is 丨 minutes~5 minutes. In this embodiment, the diameter of the nanospheres may be 4 nanometers. Please refer to Figure 7 for the arrangement of the lowest energy in the single-layered green ball, which is the arrangement of the hexagonal dense pile. The single-layer nanospheres are densely packed and have the largest duty cycle. Any three adjacent nanospheres in the single layer of nanospheres have an equilateral triangle. It can be understood that the nanospheres in the single-layer nanospheres can be arranged in a simple cubic arrangement as shown in Fig. 8 by controlling the surface tension of the nanosphere solution. 099144862 Form No. A0101 Page 15 / Total 42 Page 0992077455-0 [0038] [0039] Step S103, etching the second surface 23 of the tantalum substrate 22 with a reactive etching gas 26 while the mask layer is 24 is etched to form a plurality of stepped three-dimensional nanostructures 25 on the second surface 23 of the ruthenium substrate 22. [0041] The step of etching the second surface 23 of the tantalum substrate 22 with the reactive etching gas 26 is performed in a microwave plasma system. The microwave 荨 ion system is reactive ion etching (Reacti〇n_
Ion-Etching ’ RIE)模式。所述採用反應性蚀刻氣體 26對碎基板22的f二表面23進行姑刻的同時可對所述掩 膜層24進行雜。當所顧膜層24料層奈米微球時， 奈米微球的直徑會在_的過程中縮小，所以可形成複 數個階梯狀的三維奈米結構25。 本實施例中，將形成有單層奈米微球_基板22的第二 表面23放置於微波等離子體“巾，且紐波等離子體 系統的-感應功率源產生反應性数刻氣體26。該反應性 触刻氣體26讀㈣料轉_誠顧散並漂移至 所述夕基板22的第-表面23。，方面，所述反應性蚀刻 氣體26對所述單層奈米微球之間的所述石夕基板22的第二 表面23進純刻，從而形成第1柱252 ;另-方面，所 述反^_刻氣體26„_心基板Μ的第 二表面2 3 上的單層奈米微球進行賴，形成更小直徑的奈米微球 ，即早層奈米微球中的每—奈米微球祕刻削減為比所 述第圓柱252直徑更小的奈米微球，使所述反應性蚀刻 氣體26可對所述第—圓柱阳進行進—步㈣，從而形成 所述第二圓柱254，進而形成所述複數個階梯狀的三維奈 099144862 表單編號A01〇i 第16頁/共42頁 0992077455-0 201227997 米結構25。 [0042] 本實施例中，所述微波等離子體系統的工作氣體包括六 氟化硫（SFe)和氬氣（Ar)或六氟化硫（SF )和氧氣 0 Ο (〇2)。其中，六氟化硫的通入速率為1〇標況毫升每分 ~60標況毫升每分，氬氣或氧氣的通入速率為4標況毫升 每分~20標況毫升每分。所述工作氣體形成的氣壓為2帕 〜10柏。所述等離子體系統的功率為4〇瓦〜7〇瓦。所述採 用反應性#刻氣體26蝕刻時間為i分鐘〜2. 5分鐘。優選地 ，所述微波等離子體系綠的功率與微波等離子體系統的 工作氣體的軋壓的數值比小於2〇 :1。考以理解，通過控 制反應性蝕刻氣體26的蝕刻時間可控制三維奈米結構25 間的間距以及二維奈米結構25中所述第一圓柱252以及第 二圓柱2 5 4的向度。 [0043] Ο [0044] [0045] 進一步，所述反應性蝕刻氣體26中還可加入三氟甲烷（ CHF3)、四I曱燒（CF4)或其混合氣體等其他氣體以調 節蚀刻速率。所述三象甲垸（CHF3)、四氣甲院（％) 或其混合氣體的流量可為20標況毫升每分~40標況毫升每 分。 步驟S104，去除所述掩膜層24 ,得到所述矽片襯底。 採用四氫呋喃（THF)、丙_、丁 _、環己烷、正己烷、 甲醇或無水乙醇等無毒或低毒環保溶劑作為剝離劑，溶 解奈米微球’可去除奈綠球，保留形成切基板22中 第二表面23的三維奈米結構25，進而形成本發明第一實 施例中㈣片襯底12 ’其中’所料基妨的第一表面 099144862 表單編號A0101 第17頁/共42頁 0992077455-0 201227997 21為本發明第一實施例中所述矽片襯底12的第一表面11 :所述三維奈米結構25為本發明第一實施例中所述矽片 襯底12中的三維奈米結構15 ;所述矽基板22中相鄰的三 維奈米結構25之間的表面為本發明第一實施例中所述矽 片襯底12的第二表面13。 [0046] 本實施例中，通過在丁酮中超聲清洗去除聚苯乙烯奈米 微球。 [0047] 步驟S12，在所述三維奈米結構15的表面及相鄰三維奈米 結構15之間的矽片襯底12的第二表面13形成一摻雜矽層 14。 [0048] 所述摻雜矽層14係通過向所述三維奈米結構15的表面及 相鄰三維奈米結構1 5之間的矽片襯底1 2的第二表面1 3注 入過量的如磷或者砷等N型摻雜材料製備而成。所述摻雜 矽層14的厚度為10奈米〜1微米。所述摻雜矽層14與所述 矽片襯底12形成P-N結結構，從而實現所述太陽能電池 100中光能到電能的轉換。 [0049] 可以理解，在所述步驟S12之前，還可進一步包括在所述 三維奈米結構15的表面及相鄰三維奈米結構15之間的矽 片襯底12的第二表面13形成一本征隧道層，該本征隧道 層的材料可為二氧化矽或者氮化矽，該步驟為可選步驟 〇 [0050] 步驟S1 3，提供一上電極16，並將所述上電極16設置於所 述摻雜矽層14的至少部分表面。 [0051] 可以理解，將所述上電極1 6設置於所述摻雜矽層14的表 099144862 表單編號A0101 第18頁/共42頁 0992077455-0 201227997 Ο [0052] [0053] Ο [0054] 面’该上電極16可與所㈣雜㈣14部分接觸或完全接 觸。所述上電極16可通過所述複數個三維奈米結構⑽ 分懸空設置，並與所述摻_層14部分接觸；所述上電 極16亦可包覆於所述摻㈣層咐面並與所述推雜石夕 層14完全接觸。該上電極16可選自具有良好的透光性能 以及導電性能的銦錫氧化物結構及奈米碳管結構，以使 所述太陽能電池刚具有較高的光電轉換效率、較好的耐 用性以及均㈣電阻，從而提高所述太陽能電池100的性 能。本實施例中，所述上電極16為—奈米碳管膜，該奈 米碳管膜通過所述顯奈絲射5部分懸空設置，並與 所述摻雜_層14部分朗，該奈米碳㈣用於收 集所述 Ρ ~ Ν結中通過光能向電能轉換两庳生_電流y 步驟S14，提供一背電極1〇，將所述背電極1〇設置於所述 夕片襯底12的第一表面11，使所述背電極與所述石夕片 襯底12的第一表面Π歐姆接觸。 所述背電極10的材料可為鋁、鎂或者銀等金屬。該背電 極10的厚度為10微来〜300微米。可以理解，將所述背電 極10設置於所述矽片襯底12的第一表面丨丨，該背電極1〇 可與所述石夕片襯底12的第一表面π形成歐;姆接觸。 請參閱圖9，本發明第二實施例提供—種太陽能電池2〇〇 ，所述太％能電池200與本發明第一實施例中的太陽能電 池1 00的結構基本相同，不同之處在於，本實施例中的太 陽能電池200進一步包括一奈米級的金屬層18包覆於所述 摻雜矽層14的表面。所述金屬層18為由複數個奈米級的 金屬顆粒鋪展而成的單層層狀結構或複數層層狀結構， 099144862 表單編號A0101 第19頁/共42頁 0992077455-0 201227997 該金屬層18的厚 選自 X為2nm〜20〇nm，所述金屬層18的材料 *銀鋼、鐵或鋁等金屬材料。本實施例中，所 %屬層18為-厚度為5〇奈米左右的奈米金顆粒層。 [0055] [0056] [0057] 。^電極16亦可與所述金屬層18部分接觸或完全接觸 ^ 】中所述上電極16通過所述複數個三維奈米 結構15部分鵡办钟 。二》又置，並與所述金屬層18部分接觸。 : = ：所述摻雜矽層"的表面包覆一層奈米級的 屬岸 田入射光線透過所述上電極16照射到所述金 θ時’金屬層18的表面等離子體被激發 ，從而增加 於金屬層_相魏魏㈣紐㈣收。此外 ^層18的表面等離子體產生的電磁場亦有利於分離 陽光的激發下Pi结結構中產生的複數個電子 對。 ^八 本發明進-舟接也 ^ 、 7杈供—種所述太陽能電池200的製備方法， 氣備方法與本發明第一實施例中的太暢能電池1 〇 〇的 製備方法基本相同，不同之處在於，在所述三維奈米結 構15的表面及相鄰三維奈米結構〗5之間的矽片襯底12的 第一表面13形成一摻雜♦層14之後，進一步在所迷換雜 矽層14的表面形成一金屬層18。所述金屬層18可通過電 子束蒸發法形成於所述摻雜矽層14的表面。 [0058] 請參閱圖10，本發明第三實施例提供一種太陽能電池3〇〇 ，包括：一背電極、—矽片襯底32、一摻雜矽層34以 及一上電極36。所述石夕片襯底32具有一第一表面3丨以及 與該第一表面31相對設置的—第二表面33，所述矽片襯 099144862 表單編號A0101 第2〇頁/共42頁 0992077455-0 201227997 底的第二表面33設置有複數個三維奈米結構35，該三雉 奈米結構35為階梯狀結構；所述背電極30設置於所述石夕 片概底32的第—表面31 ’並與該第-表面31歐姆接觸； 所述摻㈣層卿心所述三轉諸構洲表面以及 相鄰二維奈米結構35之間的W概底32的第二表面33 ; 所述上電極36叹置於所述摻雜發層μ的至少部分表面。 [0059] ΟIon-Etching ’ RIE) mode. The mask layer 24 may be doped while the reactive etching gas 26 is used to align the two surfaces 23 of the fracture substrate 22. When the film layer 24 is coated with nanospheres, the diameter of the nanospheres is reduced during the process of _, so that a plurality of stepped three-dimensional nanostructures 25 can be formed. In this embodiment, the second surface 23 on which the single-layer nanosphere-substrate 22 is formed is placed in a microwave plasma, and the inductive power source of the New Wave plasma system generates a reactive gas 26. The reactive etch gas 26 is read (four), and is transferred to the first surface 23 of the substrate 22, in terms of the reactive etching gas 26 between the single layer of nanospheres. The second surface 23 of the stone substrate 22 is purely engraved to form a first pillar 252; on the other hand, the reverse gas 26 is a single layer of the second surface 2 3 of the core substrate The rice microspheres are lapped to form smaller diameter nanospheres, that is, each nanometer microsphere in the early layer of nanospheres is cut into nanospheres smaller than the diameter of the first cylinder 252. The reactive etching gas 26 may be further advanced (four) to the first cylindrical anode to form the second cylinder 254, thereby forming the plurality of stepped three-dimensional Nai 099144862 Form No. A01〇i No. 16 Page / Total 42 pages 0992077455-0 201227997 Meter structure 25. [0042] In this embodiment, the working gas of the microwave plasma system includes sulfur hexafluoride (SFe) and argon (Ar) or sulfur hexafluoride (SF) and oxygen 0 Ο (〇2). Among them, the rate of sulphur hexafluoride is 1 〇 ML per minute ~ 60 ML per minute, the access rate of argon or oxygen is 4 ML per minute ~ 20 ML per minute. The working gas forms a gas pressure of 2 Pa to 10 Pa. The plasma system has a power of 4 watts to 7 watts. 5分钟。 The etch time of the etching time is i minutes ~ 2. 5 minutes. Preferably, the numerical ratio of the power of the microwave plasma system green to the rolling pressure of the working gas of the microwave plasma system is less than 2 〇:1. It is understood that the spacing between the three-dimensional nanostructures 25 and the orientation of the first cylinders 252 and the second cylinders 25 in the two-dimensional nanostructures 25 can be controlled by controlling the etching time of the reactive etching gas 26. [0044] Further, other gases such as trifluoromethane (CHF3), tetrasulfonate (CF4), or a mixed gas thereof may be added to the reactive etching gas 26 to adjust the etching rate. The flow rate of the three elephants (CHF3), the four gas chambers (%) or a mixture thereof may be 20 standard milliliters per minute to ~40 standard milliliters per minute. Step S104, removing the mask layer 24 to obtain the enamel substrate. A non-toxic or low-toxic environmentally friendly solvent such as tetrahydrofuran (THF), propylene, butyl, cyclohexane, n-hexane, methanol or absolute ethanol is used as a stripping agent to dissolve the nanospheres to remove the nanospheres and retain the formed substrate. The three-dimensional nanostructure 25 of the second surface 23 of 22, which in turn forms the first surface of the first embodiment of the present invention, the first surface 099144862 of the substrate 12' - 0 201227997 21 is a first surface 11 of the cymbal substrate 12 in the first embodiment of the present invention: the three-dimensional nanostructure 25 is a three-dimensional shape in the cymbal substrate 12 in the first embodiment of the present invention The nanostructure 15; the surface between the adjacent three-dimensional nanostructures 25 in the tantalum substrate 22 is the second surface 13 of the wafer substrate 12 in the first embodiment of the present invention. In this example, the polystyrene nanospheres were removed by ultrasonic cleaning in methyl ethyl ketone. [0047] Step S12, forming a doped germanium layer 14 on the second surface 13 of the wafer substrate 12 between the surface of the three-dimensional nanostructure 15 and the adjacent three-dimensional nanostructure 15. [0048] The doped germanium layer 14 is implanted in excess by, for example, a surface of the three-dimensional nanostructure 15 and a second surface 13 of the wafer substrate 12 between adjacent three-dimensional nanostructures 15 An N-type doping material such as phosphorus or arsenic is prepared. The doped germanium layer 14 has a thickness of 10 nm to 1 μm. The doped germanium layer 14 forms a P-N junction structure with the germanium substrate 12, thereby effecting conversion of light energy to electrical energy in the solar cell 100. [0049] It can be understood that, before the step S12, the second surface 13 of the cymbal substrate 12 between the surface of the three-dimensional nanostructure 15 and the adjacent three-dimensional nanostructure 15 may be further formed. In the intrinsic tunnel layer, the material of the intrinsic tunnel layer may be ceria or tantalum nitride. This step is an optional step [0050] Step S13, an upper electrode 16 is provided, and the upper electrode 16 is disposed. At least part of the surface of the doped germanium layer 14. [0051] It can be understood that the upper electrode 16 is disposed on the doped germanium layer 14 of the table 099144862. Form No. A0101 Page 18 / Total 42 Page 0992077455-0 201227997 Ο [0054] [0054] The upper electrode 16 can be in contact with or in full contact with the (iv) (four) 14 portion. The upper electrode 16 may be suspended by the plurality of three-dimensional nanostructures (10) and partially in contact with the doped layer 14; the upper electrode 16 may also be coated on the doped (four) layer and The pusher layer 14 is in full contact. The upper electrode 16 may be selected from an indium tin oxide structure and a carbon nanotube structure having good light transmission properties and electrical conductivity, so that the solar cell has high photoelectric conversion efficiency, good durability, and The resistance is (4), thereby improving the performance of the solar cell 100. In this embodiment, the upper electrode 16 is a carbon nanotube film, and the carbon nanotube film is suspended by the pentaline portion 5 and is partially overlapped with the doping layer 14 The rice carbon (4) is used for collecting the Ρ~ Ν junction, and converting the two 庳 current y to the electric energy by the light energy, step S14, providing a back electrode 1〇, and disposing the back electrode 1〇 on the mat substrate The first surface 11 of the 12 is such that the back electrode is in ohmic contact with the first surface of the slab substrate 12. The material of the back electrode 10 may be a metal such as aluminum, magnesium or silver. The back electrode 10 has a thickness of 10 micrometers to 300 micrometers. It can be understood that the back electrode 10 is disposed on the first surface 丨丨 of the cymbal substrate 12, and the back electrode 1 形成 can form a contact with the first surface π of the slab substrate 12; . Referring to FIG. 9, a second embodiment of the present invention provides a solar cell 2, which has substantially the same structure as the solar cell 100 in the first embodiment of the present invention, except that The solar cell 200 in this embodiment further includes a nano-scale metal layer 18 overlying the surface of the doped germanium layer 14. The metal layer 18 is a single layered structure or a plurality of layered structures spread by a plurality of nano-sized metal particles, 099144862 Form No. A0101 Page 19 / Total 42 Page 0992077455-0 201227997 The metal layer 18 The thickness is selected from the range of X of 2 nm to 20 〇 nm, and the material of the metal layer 18 is a metal material such as silver steel, iron or aluminum. In the present embodiment, the % layer 18 is a layer of nano gold particles having a thickness of about 5 nanometers. [0057] [0057]. The electrode 16 may also be in partial or complete contact with the metal layer 18. The upper electrode 16 passes through the plurality of three-dimensional nanostructures 15 portions of the clock. The second is placed again and partially in contact with the metal layer 18. : = : the surface of the doped germanium layer is coated with a layer of nanometer-scale incident light passing through the upper electrode 16 to the gold θ. The surface plasma of the metal layer 18 is excited, thereby increasing In the metal layer _ phase Wei Wei (four) New (four) received. In addition, the electromagnetic field generated by the surface plasmon of layer 18 is also advantageous for separating a plurality of pairs of electrons generated in the Pi junction structure excited by sunlight. The invention provides a method for preparing the solar cell 200, and the method for preparing the solar cell is basically the same as the method for preparing the solar cell of the first embodiment of the present invention. The difference is that after the surface of the three-dimensional nanostructure 15 and the first surface 13 of the cymbal substrate 12 between the adjacent three-dimensional nanostructures 15 form a doping layer 14, further A metal layer 18 is formed on the surface of the hybrid layer 14. The metal layer 18 may be formed on the surface of the doped germanium layer 14 by an electron beam evaporation method. Referring to FIG. 10, a third embodiment of the present invention provides a solar cell 3A comprising: a back electrode, a germanium substrate 32, a doped germanium layer 34, and an upper electrode 36. The slab substrate 32 has a first surface 3A and a second surface 33 disposed opposite the first surface 31. The lining lining 099144862 Form No. A0101 Page 2 / Total 42 Page 0992077455- 0 201227997 The second surface 33 of the bottom is provided with a plurality of three-dimensional nanostructures 35, which are stepped structures; the back electrode 30 is disposed on the first surface 31 of the stone base 32 And ohmic contact with the first surface 31; the doped (four) layer of the third surface 33 of the three-converted surface and the adjacent two-dimensional nanostructure 35; The upper electrode 36 is placed on at least a portion of the surface of the doped layer μ. [0059] Ο
[0060] 099144862 所述太陽能電池3G()與本㈣實施财的太陽能電池 1〇〇的結構基本相同，不同之處在於，本實施例中，所述 三維奈米結構35為—階梯狀凹陷結構，所述階梯狀凹陷 、、。構為從所迷碎片_底32的第二表面㈣内凹陷形成的 階梯狀凹陷的空間，即為-皮體結構。、所述階梯狀凹 陷結構為1數層結構，如複數層三棱臺、複數層四棱 臺、層、棱臺、複數層圓柱或複數層圓臺等。所述 階梯狀凹_構的最大尺寸為小於等於1GG0奈米，即其 長度、寬度和高度均小於等於—奈米。優選地，所述 階梯狀凹陷結構的長度、寬度和高度範圍為㈣米~5〇〇 結構。所謂階梯狀凹陷結構為複數層_結構係指所述 階梯狀凹陷的空間為複數層圓柱形狀。 請參閱圖11，本實施例中，所述二 ^ —维奈米結構35的形狀 為一雙:圓挺狀空間，具體包括—第1柱狀空間352, 以及一所、^第―圓柱狀空間352連通㈣二圓柱狀空間 354。所迷第一圓柱狀空間352與第二 ^ ^ ^ ^ 圓狀空間354同 轴s又置。所迷第—圓柱狀空間352靠 非处矽片襯底32的第二 表面又置。所述第一圓枉狀空間3 6的直徑大於第二圓 表單編號A0101 第21頁/共42頁 0992077455-0 201227997 柱狀空間354的直徑。所述第一圓柱狀空間352的直徑為 30奈米〜1 000奈米，高度為50奈米〜1 000奈米。所述第二 圓柱狀空間354的直徑為10奈米〜500奈米，高度為20奈 米〜500奈米。所述第一圓柱狀空間352以及第二圓柱狀空 間354的尺寸可根據實際需要製備。 [0061] 所述複數個三維奈米結構35在所述矽片襯底32上的第二 表面33以陣列形式設置。所述以陣列形式設置指所述複 數個三維奈米結構35可按照簡單立方排布、同心圓環排 布或六角形密堆排布等方式排列，而且所述以陣列形式 設置的複數個三維奈米結構35可形成一個單一圖案或複 數個圖案。所述相鄰的兩個三維奈米結構35之間的距離 相等。所述相鄰的兩個三維奈米結構35之間的距離為1 0 奈米〜1 000奈米。所述複數個三維奈米結構35在所述矽片 襯底32上的第二表面33設置的形式以及相鄰的兩個三維 奈米結構35之間的距離可根據實際需要製備。本實施例 中，所述複數個三維奈米結構35呈六角形密堆排布形成 一單一正方形圖案，且相鄰兩個三維奈米結構35之間的 距離約為50奈米。 [0062] 可以理解，在所述矽片襯底32的第二表面33設置複數個 奈米級的階梯狀凹陷結構可使所述矽片襯底32的第二表 面33具有較大的P-N結的界面面積，從而提高所述太陽能 電池300的光電轉換效率。此外，當光線照射到所述階梯 狀凹陷結構時，該照射的光線可在所述階梯狀凹陷結構 中發生複數次反射並吸收，從而增加了所述摻雜矽層的 陷光性能；此外，所述複數個三維奈米結構35亦具有光 099144862 表單編號A0101 第22頁/共42頁 0992077455-0 201227997 子曰體的特性，還可增加光子在所述三維 滯留蚌Η,、， 卞結構35的 间从及三維奈米結構35的吸收光的頻礙# 而接古 卞％圍，從 同所述太陽能電池300吸光效率，進而撻古 銥雷妯^叫所述太陽 月b電池30〇的光電轉換效率。 [0063] 可以理解’所述太陽能電池3GG亦可進-步y 道層（圖中未示），該本征隧道層設置於所迷 / 32及摻㈣心之間。該本㈣道層可降低底* 穴對在所述矽片襯底32和摻雜矽層34接觸面的複人速产" Ο ’從而進一步提高所述太陽能電池3〇 〇的 又 屮休，祕、少 电轉換效率。 此汗所述太陽能電鳴3 0 還可進一步包括—太 s , 帑米級的金 屬層（圖中未示），該金屬層包覆於所述摻雜砂層34表 面。該金屬層與本發明第二實施例中的金屬層Μ具有相 同的材料和厚度。 、 [0064] Ο 本發明進—步提供一種所述太陽能電他300的製僙方法， 所述製備料與树實闕巾的场⑼池1〇〇的 製備方法基本相同，不同之處在於，由於本實施例中的 三維奈米結構為階梯狀凹陷結構，辦以，本實施例中 在所述絲板22的第二表面23形成-具有複數個開孔的 連續膜作為所述掩膜層24。可以理解，採用具有複數個 開孔的連續膜作為掩膜層24時’-方面’所述反應錢 刻氣體26對所述連續膜中對應開孔部分的梦基板22第二 表面23進行蝕刻’從而形成第二圓柱狀空間354 ; 面’所述反應性蚀刻氣體26同時對所述妙基板μ的第__ 表面23上的連續膜進行純，使所述連續膜中的開孔變 大，使所述反應性蝕刻氣體26對所述矽基板22第二表面 099144862 表單編號A0101 第23頁/共42頁 0992077455-0 201227997 23的蝕刻範圍更大，從而形成所述第一圓柱狀空間352， 最後在開孔對應的位置製備得到階梯狀凹陷結構。可以 理解，通過控制反應性蝕刻氣體26的蝕刻時間可控制三 維奈米結構35間的間距以及三維奈米結構35中所述第一 圓柱狀空間352以及第二圓柱狀空間354的尺寸。所述具 有複數個開孔的連續膜可通過奈米壓印、模板沈積等方 式製備。 [0065] 本發明實施例的太陽能電池具有以下優點：首先，在所 述矽片襯底的表面設置複數個階梯狀的三維奈米結構， 可提高所述太陽能電池的取光面積；其次，所述階梯狀 凸起結構或階梯狀凹陷結構可使入射的太陽光在所述階 梯狀凸起結構或階梯狀凹陷結構發生複數次反射及吸收 ，從而增加了所述摻雜矽層的陷光性能以及所述太陽能 電池對各個方向的光吸收效率，故，可提高所述太陽能 電池對光線的利用率；再次，在所述摻雜矽層的表面包 覆一層奈米級的金屬層，當入射光線透過所述太陽能電 池的上電極照射到所述金屬層時，由於金屬層的表面等 離子效應，可增加所述金屬層附近的摻雜矽層對光子的 吸收性能，並有利於分離在太陽光的激發下P-N結結構中 產生的複數個電子-空穴對；最後，所述階梯狀的三維奈 米結構還具有光子晶體的特性，可增加光子在所述三維 奈米結構的滯留時間以及三維奈米結構的吸收太陽光的 頻率範圍，進而提高所述太陽能電池的光電轉換效率。 [0066] 本發明實施例所述太陽能電池的製備方法，該方法通過 掩膜層和反應性蝕刻氣體相結合的方法，可在所述矽片 099144862 表單編號A0101 第24頁/共42頁 0992077455-0 201227997 襯底的第二表面形成階梯狀的三維奈米結構以增加所述 太陽能電池的取光面積，且該方法工藝簡單，成本低廉 0 [0067] 綜上所述，本發明確已符合發明專利之要件，遂依法提 出專利申請。惟，以上所述者僅為本發明之較佳實施例 ，自不能以此限制本案之申請專利範圍。舉凡習知本案 技藝之人士援依本發明之精神所作之等效修飾或變化， 皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 [0068] 圖1為先前技術中的太陽能電池的結構示意圖。 [0069] 圖2為本發明第一實施例提供的太陽能電池的結構示意圖 〇 [0070] 圖3為本發明第一實施例提供的太陽能電池中矽片襯底的 結構示意圖。 [0071] 圖4為本發明第一實施例提供的太陽能電池中矽片襯底的 掃描電鏡照片。 [0072] 圖5為本發明第一實施例提供的太陽能電池的製備方法的 流程圖。 [0073] 圖6為本發明第一實施例提供的太陽能電池的製備方法中 在矽基板的第二表面形成複數個三維奈米結構的製備方 法的工藝流程圖。 [0074] 圖7為本發明第一實施例提供的太陽能電池的製備方法中 在矽基板的第二表面形成六角形密堆排布的單層奈米微 099144862 表單編號A0101 第25頁/共42頁 0992077455-0 201227997 球的掃描電鏡照片。 [0075] 圖8為本發明第一實施例提供的太陽能電池的製備方法中 在矽基板的第二表面形成簡單立方排布之單層奈米微球 的掃描電鏡照片。 [0076] 圖9為本發明第二實施例提供的太陽能電池的結構示意圖 〇 [0077] 圖1 0為本發明第三實施例提供的太陽能電池的結構示意 圖。 [0078] 圖11為本發明第三實施例提供的太陽能電池中矽片襯底 的結構示意圖。 【主要元件符號說明】 [0079] 太陽能電池：100 ; 200 ; 300 [0080] 背電極：1 0 ; 3 0 [0081] 第一表面：11;21;31 [0082] 矽片襯底：12 ; 32 [0083] 第二表面：13 ; 23 ; 33 [0084] 摻雜矽層：14 ; 34 [0085] 三維奈米結構：1 5 ; 2 5 ; 3 5 [0086] 第一圓柱：152 ; 252 [0087] 第二圓柱：154 ; 254 [0088] 上電極：16 ; 36 099144862 表單編號A0101 第26頁/共42頁 0992077455-0 201227997 [0089] 金屬層：18 [0090] 矽基板：22 [0091] 掩膜層：24 [0092] 反應性蝕刻氣體：26 [0093] 第一圓柱狀空間：352 [0094] 第二圓柱狀空間：354 〇 099144862 表單編號A0101 第27頁/共42頁 0992077455-0[0060] 099144862 The solar cell 3G () and the (four) implementation of the solar cell 1 〇〇 structure is basically the same, in this embodiment, the three-dimensional nanostructure 35 is a stepped recess structure , the stepped depression, . The space which is formed as a stepped depression formed by the depression in the second surface (four) of the debris_bottom 32 is a --sheath structure. The stepped recessed structure is a plurality of layers, such as a plurality of triangular strut, a plurality of quadrangular strata, a layer, a prism, a plurality of layers, or a plurality of round tables. The maximum dimension of the stepped concave structure is 1GG0 nm or less, that is, its length, width and height are less than or equal to - nanometer. Preferably, the stepped recessed structure has a length, a width and a height ranging from (four) meters to 5 inches. The stepped recessed structure is a plurality of layers. The structure means that the space of the stepped recess is a plurality of cylindrical shapes. Referring to FIG. 11 , in the embodiment, the shape of the two-dimensional Venn structure 35 is a double: a rounded space, specifically including a first columnar space 352, and a first, a second column. The space 352 is connected to (four) two cylindrical spaces 354. The first cylindrical space 352 and the second ^^^^ circular space 354 are disposed in the same axis s. The first cylindrical space 352 is again disposed on the second surface of the non-defective substrate 32. The diameter of the first circular-shaped space 316 is larger than the second circle. Form No. A0101 Page 21 of 42 0992077455-0 201227997 The diameter of the columnar space 354. The first cylindrical space 352 has a diameter of 30 nm to 1 000 nm and a height of 50 nm to 1 000 nm. The second cylindrical space 354 has a diameter of 10 nm to 500 nm and a height of 20 nm to 500 nm. The dimensions of the first cylindrical space 352 and the second cylindrical space 354 can be prepared according to actual needs. [0061] The plurality of three-dimensional nanostructures 35 are disposed in an array on the second surface 33 on the cymbal substrate 32. The arrangement in the form of an array means that the plurality of three-dimensional nanostructures 35 can be arranged in a simple cubic arrangement, a concentric annular arrangement or a hexagonal dense arrangement, and the plurality of three-dimensional images are arranged in an array form. The nanostructures 35 can form a single pattern or a plurality of patterns. The distance between the adjacent two three-dimensional nanostructures 35 is equal. The distance between the adjacent two three-dimensional nanostructures 35 is from 10 nm to 1 000 nm. The form in which the plurality of three-dimensional nanostructures 35 are disposed on the second surface 33 of the cymbal substrate 32 and the distance between the adjacent two three-dimensional nanostructures 35 can be prepared according to actual needs. In this embodiment, the plurality of three-dimensional nanostructures 35 are arranged in a hexagonal densely packed pattern to form a single square pattern, and the distance between adjacent two three-dimensional nanostructures 35 is about 50 nm. [0062] It can be understood that a plurality of nano-scale stepped recess structures are disposed on the second surface 33 of the cymbal substrate 32 to enable the second surface 33 of the cymbal substrate 32 to have a larger PN junction. The interface area, thereby increasing the photoelectric conversion efficiency of the solar cell 300. In addition, when light is irradiated to the stepped recessed structure, the irradiated light may be reflected and absorbed in the stepped recessed structure for a plurality of times, thereby increasing the light trapping performance of the doped germanium layer; The plurality of three-dimensional nanostructures 35 also have the characteristics of light 099144862 Form No. A0101, page 22/42, 0992077455-0 201227997, and can also increase the photon in the three-dimensional stagnation 、, , structure 35 Between the three-dimensional nanostructures 35 and the absorption of light, and the absorption of light from the same solar cell 300, and then the solar b 铱 妯 ^ said the solar moon b battery 30 〇 Photoelectric conversion efficiency. [0063] It can be understood that the solar cell 3GG can also be advanced into a layer (not shown) disposed between the 520 and the doped (four) core. The (four) track layer can reduce the bottom of the hole to the contact surface of the enamel substrate 32 and the doped yttrium layer 34 to further improve the solar cell 3 〇〇 , secret, less electricity conversion efficiency. The sweating solar electric ring 30 may further include a metal layer (not shown) of the s, glutinous grade, which is coated on the surface of the doped sand layer 34. The metal layer has the same material and thickness as the metal layer of the second embodiment of the present invention. [0064] The present invention further provides a method for preparing the solar electric battery 300, wherein the preparation material is substantially the same as the preparation method of the field (9) pool 1〇〇 of the tree towel, except that Since the three-dimensional nanostructure in this embodiment is a stepped recess structure, in the present embodiment, a continuous film having a plurality of openings is formed on the second surface 23 of the silk plate 22 as the mask layer. twenty four. It can be understood that when a continuous film having a plurality of openings is used as the mask layer 24, the reaction gas 26 etches the second surface 23 of the dream substrate 22 corresponding to the opening portion of the continuous film. Thereby forming a second cylindrical space 354; the surface of the reactive etching gas 26 simultaneously purifies the continuous film on the __ surface 23 of the substrate μ, making the opening in the continuous film large, The reactive etching gas 26 is made to have a larger etching range of the second surface 099144862 of the 矽 substrate 22, Form No. A0101, 23//42, 0992077455-0 201227997 23, thereby forming the first cylindrical space 352, Finally, a stepped recessed structure is prepared at a position corresponding to the opening. It can be understood that the spacing between the three-dimensional nanostructures 35 and the dimensions of the first cylindrical space 352 and the second cylindrical space 354 in the three-dimensional nanostructure 35 can be controlled by controlling the etching time of the reactive etching gas 26. The continuous film having a plurality of openings can be prepared by nanoimprinting, template deposition, or the like. [0065] The solar cell of the embodiment of the present invention has the following advantages: first, a plurality of stepped three-dimensional nanostructures are disposed on the surface of the enamel substrate, thereby improving the light extraction area of the solar cell; secondly, The stepped convex structure or the stepped concave structure can reflect and absorb incident sunlight in the stepped convex structure or the stepped concave structure, thereby increasing the light trapping performance of the doped germanium layer. And the light absorption efficiency of the solar cell in various directions, so that the utilization rate of the solar cell for light can be improved; again, a surface of the doped germanium layer is coated with a nano-scale metal layer when incident When light is transmitted through the upper electrode of the solar cell to the metal layer, due to the surface plasma effect of the metal layer, the absorption of photons by the doped germanium layer in the vicinity of the metal layer can be increased, and the separation in sunlight is facilitated. Exciting a plurality of electron-hole pairs generated in the PN junction structure; finally, the stepped three-dimensional nanostructure also has the characteristics of a photonic crystal, Increasing photon residence time in the frequency range of the three-dimensional nanostructures absorb sunlight and three Weinai Mi structure, thereby improving the photoelectric conversion efficiency of the solar cell. [0066] A method for preparing a solar cell according to an embodiment of the present invention, wherein the method is combined with a masking layer and a reactive etching gas, and the method can be used in the cymbal 099144862 Form No. A0101 Page 24 / Total 42 Page 0992077455- 0 201227997 The second surface of the substrate forms a stepped three-dimensional nanostructure to increase the light extraction area of the solar cell, and the method is simple in process and low in cost. [0067] In summary, the present invention has indeed met the invention. The requirements of the patent, 提出 file a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS [0068] FIG. 1 is a schematic structural view of a solar cell in the prior art. 2 is a schematic structural view of a solar cell according to a first embodiment of the present invention. [0070] FIG. 3 is a schematic structural view of a ruthenium substrate in a solar cell according to a first embodiment of the present invention. 4 is a scanning electron micrograph of a ruthenium substrate in a solar cell according to a first embodiment of the present invention. 5 is a flow chart of a method of fabricating a solar cell according to a first embodiment of the present invention. 6 is a process flow diagram of a method for preparing a plurality of three-dimensional nanostructures on a second surface of a tantalum substrate in a method for fabricating a solar cell according to a first embodiment of the present invention. 7 is a single-layer nano-micro 099144862 form a hexagonal close-packed arrangement on a second surface of a ruthenium substrate in the method for fabricating a solar cell according to a first embodiment of the present invention. Form No. A0101 Page 25 of 42 Page 0992077455-0 201227997 Scanning electron micrograph of the ball. 8 is a scanning electron micrograph of a single-layer nanosphere formed on a second surface of a tantalum substrate in a method for preparing a solar cell according to a first embodiment of the present invention. 9 is a schematic structural view of a solar cell according to a second embodiment of the present invention. [0077] FIG. 10 is a schematic structural view of a solar cell according to a third embodiment of the present invention. 11 is a schematic structural view of a ruthenium substrate in a solar cell according to a third embodiment of the present invention. [Description of main component symbols] [0079] Solar cell: 100; 200; 300 [0080] Back electrode: 10; 3 0 [0081] First surface: 11; 21; 31 [0082] 矽 substrate: 12; 32 [0083] Second surface: 13; 23; 33 [0084] Doped yttrium layer: 14; 34 [0085] Three-dimensional nanostructure: 1 5 ; 2 5 ; 3 5 [0086] First cylinder: 152; 252 [0087] Second cylinder: 154; 254 [0088] Upper electrode: 16; 36 099144862 Form number A0101 Page 26/Total 42 page 0992077455-0 201227997 [0089] Metal layer: 18 [0090] 矽 substrate: 22 [0091 Mask layer: 24 [0092] Reactive etching gas: 26 [0093] First cylindrical space: 352 [0094] Second cylindrical space: 354 〇 099144862 Form number A0101 Page 27 / Total 42 page 0992077455-0