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Title: Zn/sub 3/P/sub 2/ as an improved semiconductor for photovoltaic solar cells. Eleventh quarterly report, March 1, 1981-May 31, 1981

Technical Report ·
OSTI ID:6317526

Mg/Zn/sub 3/P/sub 2/ devices were prepared on thin Zn/sub 3/P/sub 2/ films grown on mica/Fe/Si substrates. The highest total area conversion efficiency achieved on a 1 cm/sup 2/ area cell under smulated AM-1 illumination was 4.3%. The seris resistance in the cells was less than or equal to 5 ..cap omega.. cm/sup 2/ and a fill factor as high as 57% was observed. The J/sub sc/ (approx. 17 mA/cm/sup 2/) was compared to similar devices on large grain bulk Zn/sub 3/P/sub 2/ wafers. Spectral response and laser spot scans indicate a longer electron diffusion length in these films compared to films prepared on mica/Fe/C silicon steel substrates. The series resistance in the devices decreased at higher temperatures. It appears that the back contact resistance is a major contributing factor to the total series resistance of the device. The composition of this Zn/sub 3/P/sub 2/ films grown by close-spaced vapor transport on mica substrates was determined by x-ray fluorescence analysis. Electron beam induced current (EBIC) measurements were made on a Mg/Zn/sub 3/P/sub 2/ device and the surface recombination velocity was determined to be approx. 10/sup 2/ cm/sec. Attempts were made to measure the drift mobility in bulk and thin film Zn/sub 3/P/sub 2/. Experiments are being conducted to prepare high resistivity Zn/sub 3/P/sub 2/ to see the evidence of n type conductivity by annealing in Zn at temperatures up to 925/sup 0/C. Seeded crystal growth, using a seed with (101) plane at an angle to the saw cut face resulted in a boule with 2-3 large grains. The performance of ZnO/Zn/sub 3/P/sub 2/ devices has been lower than expected. The V/sub oc/ in these devices is < 0.4 Volts and the maximum active area conversion efficiency has been approx. 2%.

Research Organization:
Delaware Univ., Newark (USA). Inst. of Energy Conversion
DOE Contract Number:
AC02-77CH00178
OSTI ID:
6317526
Report Number(s):
SERI/PR-8062-1-T11; ON: DE81027505
Country of Publication:
United States
Language:
English