US 12,148,854 B2
Method for producing a double graded CdSeTe thin film structure
Shou Peng, Shanghai (CN); Xinjian Yin, Shanghai (CN); Ganhua Fu, Shanghai (CN); Daniele Menossi, Dresden (DE); Michael Harr, Kelkheim-Ruppertshain (DE); and Bastian Siepchen, Dresden (DE)
Assigned to China Triumph International Engineering Co., Ltd., Shanghai (CN); and CTF Solar GmbH, Dresden (DE)
Appl. No. 17/629,576
Filed by CHINA TRIUMPH INTERNATIONAL ENGINEERING CO., LTD., Shanghai (CN); and CTF SOLAR GMBH, Dresden (DE)
PCT Filed Jul. 25, 2019, PCT No. PCT/CN2019/097601
§ 371(c)(1), (2) Date Jan. 24, 2022,
PCT Pub. No. WO2021/012241, PCT Pub. Date Jan. 28, 2021.
Prior Publication US 2022/0246786 A1, Aug. 4, 2022
Int. Cl. H01L 31/18 (2006.01); H01L 31/0296 (2006.01); H01L 31/065 (2012.01); H01L 31/073 (2012.01)
CPC H01L 31/1832 (2013.01) [H01L 31/02966 (2013.01); H01L 31/065 (2013.01); H01L 31/02963 (2013.01); H01L 31/073 (2013.01); Y02E 10/543 (2013.01)] 13 Claims
OG exemplary drawing
 
1. Method for forming a double-graded CdSeTe thin film comprising the steps:
a) providing a base substrate,
b) forming a first CdSewTe1-w layer having a first thickness d1 and a first amount w1 of selenium in it on the base substrate,
c) forming a second CdSewTe1-w layer having a second thickness d2 and a second amount w2 of selenium in it on the first CdSewTe1-w layer, wherein the second amount w2 lies in the range between 0.25 and 0.4, and
d) forming a third CdSewTe1-w layer having a third thickness d3 and a third amount w3 of selenium in it on the second CdSewTe1-w layer,
wherein a maximum of the energy gap in the first CdSewTe1-w layer and a maximum of the energy gap in the third CdSewTe1-w layer are equal to or higher than 1.45 eV and the energy gap in the second CdSewTe1-w layer lies in the range between 1.38 eV and 1.45 eV and is smaller than the maximum of the energy gap in the first CdSewTe1-w layer and smaller than the maximum of the energy gap in the third CdSewTe1-w layer;
wherein at least the first or the third CdSewTe1-w layer is formed using deposition of a layer of CdSe and/or a layer of CdTe and annealing the deposited layers,
the first CdSewTe1-w layer is formed using consecutive deposition of a first layer of CdSe with a first thickness d11 and a second layer of CdTe with a second thickness d22 and annealing the deposited layers at a first temperature and under a first atmosphere for a first time period,
the second CdSewTe1-w layer is formed using consecutive deposition of a second layer of CdSe with a third thickness d21 and a second layer of CdTe with a fourth thickness d22 and annealing the deposited layers at a second temperature and under a second atmosphere for a second time period, and
the third CdSewTe1-w layer is formed using consecutive deposition of a third layer of CdSe with a fifth thickness d31 and a third layer of CdTe with a sixth thickness d32 and annealing the deposited layers at a third temperature and under a third atmosphere for a third time period,
wherein the ratio of the respective thickness of the CdSe layer and the respective thickness of the CdTe layer is different for each of the first, the second and the third CdSewTe1-w layer.