Development of 1.25 eV InGaAsN for triple junction solar cells Page: 4 of 5
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
thinner InGaAsN bases are used because growth of InGaAsN requires a large amount of
dimethylhydrazine, and hence growth of thick layers is expensive. Trimethylgallium,
triethylgallium, solution trimethylindium, diethylzinc, disilane, arsine, and phosphine are
the other precursors used in the growth of the devices. Cells 1 cm2 in area are processed
using standard III-V device processing techniques.
Metal
n+-GaAs
0.5 m
7 x 1018 cm 3
n+-InGaP2 0.7 pm 2 x 10 cm3
n+-InGaAsN 0.2 m 2 x 1018 cm3
p-InGaAsN 1.5 m 2 x 1017 cm3
p-GaAs 1 Jim 5 x 10 cmi
p-GaAs Substrate
Metal
Figure 1. Schematic of the basic InGaAsN cell structure.
Table 1 contains a summary of different InGaAsN growth conditions that we
have examined. We have primarily looked at growth rate and post-growth annealing
temperature. We have also used several different dimethylhydrazine sources from
different vendors, but have seen little effect on device results.
Run# Window Mat'l W(A) BSF Mat'i BSF(A) Base(gm) Emitter(gm) Rg (A/s) 650 C, N2
9ky034-02 InGaP 6700 GaAs 500 3 0.2 -20 4 mins
91y01A-06 InGaP 5450 GaAs 500 3 0.1 -20 4 mins
91y01 B-03 InGaP 5450 GaAs 500 3 0.1 -20 30 mins
91y06A-06 InGaP 6700 (AI)GaAs 250 1.2 0.2 -12 30 mins
9iy06B-06 InGaP 6700 (AI)GaAs 250 1.2 0.2 -12 45 mins
91y019-06 InGaP 6700 (AI)GaAs 250 1.2 0.2 -7.2 30 mins
Oay18A-06 InGaP 6700 (AI)GaAs 250 1.8 0.2 -7.2 45 mins
Oayl8B-05 InGaP 6700 (AI)GaAs 250 1.8 0.2 -7.2 60 mins
Table 1. Summary of growth conditions and structure for InGaAsN solar cells. W(A)
refers to the window thickness in angstroms, Rg (A/s) refers to the growth rate in
angstroms/sec, and 650"C, N2 refers to the post growth annealing time and temperature.
Table 2 has the device results for the growth conditions described in Table 1. The
currents, voltages, and fill factors all lower than expected for a material with bandgap of
1.25 eV. To be current matched with a GaInP2 upper cell in a triple junction device, the
InGaAsN would need to generate about 20 mA/cm2. The devices do not have an anti-
reflection coating (ARC). Reflection off of the front surface is about 30%, so addition of
the ARC would add about 3-4 mA/cm2 to the currents shown in Table 2. Increasing the
base thickness does not add significantly to the current. Figure 2 has the IQE curves for
several of the devices in Tables 1 and 2. While being able to achieve a peak IQE close to
the band edge, there is significant roll off at longer wavelengths. An increased base-2-
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Li, N. Y.; Sharps, P. R.; Hills, J. S.; Hou, H.; Chang, Ping-Chih & Baca, Albert G. Development of 1.25 eV InGaAsN for triple junction solar cells, article, May 16, 2000; Albuquerque, New Mexico. (https://digital.library.unt.edu/ark:/67531/metadc708595/m1/4/: accessed April 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.