Photoelectronic Properties of CdTe Films Sintered with $CdCl_2$ and $CuCl_2$

$CdCl_2$와 $CuCl_2$ 양에 따른 CdTe 소결막의 광전기적 성질

The photoelectronic properties of CdTe films sintered with various amounts of $CdCl_2$ and $CuCl_2$ have been investigated by measurements of dark electrical resistivity, photocurrent, thermoelectric power, optical transmission and by observation of microstructure. The grain size and optical transmission of sintered CdTe films increase with increasing amount of $CdCl_2$ indicating that $CdCl_2$ acts as a sintering aid. The photoconductivity gain(A-$cm^2/W$) increases and resistivity($\Omega$-cm) decreases with increasing amount of $CuCl_2$ up to 100ppm due to the occurance of Cu-doping during sintering. The dark resistivity could be reduced farther by post heat treatments. The dark resistivity was still high($10^3{\Omega}$-cm) so that the accurate determination of the hole concentration by Hall measurement or by thermoelectric power measurement was not possible. From the analysis of electrical activation energy, however it can be concluded that the hole concentration is less than $10^{14}/cm^3$ and all grains are depleted of carrier by the trapping centers at grain boundaries.