模擬氮化銦鎵太陽能電池在非極性面藍寶石基版上生長

Abstract

本論文主要研究是利用APSYS的模擬軟體，來優化氮化銦鎵太陽能電池之結構，並且探討方法1：固定吸收層厚度為300 nm和不同銦含量組成，建立一個雙異質接面p-i-n結構之氮化銦鎵太陽能電池，模擬不同銦含量組成所造成的特性影響。此元件中不同吸收層的銦含量，會有不同的光吸收量，銦含量較多，雖然可以增加光的吸收量，但因能隙的改變，而影響太陽能電池的短路電流與轉換效率。方法2：固定吸收層的銦含量組成為35％和改變吸收層厚度，吸收層厚度的條件為50~500 nm，建立一個雙異質接面元件p-i-n結構之氮化銦鎵太陽能電池，其中不同吸收層的厚度，會有不同的光吸收量，較厚雖然可增加光吸收量，但相對的串聯電阻與暗電流等特性皆會因厚度增加而增加，而影響太陽能電池的短路電流與轉換效率。方法3：固定吸收層厚度為300 nm，建立一個多異質接面元件p-i-n結構之氮化銦鎵太陽能電池，並且漸變其厚度與銦含量，改變單一吸收層原本能隙不連續的狀態，大幅提升短路電流、轉換效率，量測效率結果發現，雙異質接面元件p-i-n結構之氮化銦鎵太陽能電池元件之短路電流為9.63 mA/cm2 ，改成多異質接面元件p-i-n結構之氮化銦鎵太陽能電池元件可增加為59.84 mA/cm2，轉換效率由11.2 %增加為27.66 %，相對提昇16.46 %。由此發現，此多異質接面元件p-i-n結構之氮化銦鎵太陽能電池元件結構，的確有利於氮化銦鎵太陽能電池。

Before 2002 pepole define the bandgap of GaN is 3.4 eV. The bandgap of InN is 1.9 ~ 2.0 eV. After 2002 U.S. Department of Energy's Lawrence Berkeley National Laboratory of Dr.Wladek Walukiewicz. He got different results . The experimental results show that InN material bandgap is 0.7 eV. So that the bandgap of InGaN range from 0.7 ~ 3.4 eV. APSYS is a Simulation Software. We use APSYS researching for InGaN solar cell.We use APSYS to simulation InGaN solar cell. Method 1 - Fixed active layer and change the doping concentration. (Thickness : 300 nm InXGa1-XN x = 0.05 ~ 0.5). We simulation a double hetero-junction p-i-n solar cells. The device with different In content. It got different light absorption. More doping concentration to get more light absorption. Bandgap is change. It affects the solar cell conversion efficiency and short circuit current. Method 2 – Fixed indium content of active layer. Change Absorbing layer thickness.( InXGa1-XN x = 0.35、Thickness : 50 ~ 500 nm). We simulation a InGaN double hetero -junction p-i-n solar cells. Different absorption layer thickness gets the different light absorption.Thicker thickness increase light absorption. But the relative series resistance and dark current will be big. It affects solar cell short circuit current and conversion efficiency. Method 3 – Fixed indium content of absorbing layer. (Thickness :300 nm).We simulation a InGaN mulit-hetero -junction p-i-n solar cells. We grading thickness and indium content. The active layer with grading indium composition at interface can smooth the bandgap discontinuity. The maximal efficiency of InGaN solar cells is 27.66% which includes 60% indium and the thick of grading layers are 2 nm.