Room temperature photocurrent spectroscopy of SiGe/Si p-i-n photodiodes grown by selective epitaxy

We present the photocurrent spectroscopy of Si/sub 1-x/Ge/sub x//Si double heterostructure p-i-n diodes selectively grown by low pressure chemical vapor deposition. The growth onto patterned wafers permits to obtain dislocation-free, fully strained Si/sub 1-x/Ge/sub x/ layers, much above the critical thickness. The band gap energy of Si/sub 1-x/Ge/sub x/ was determined at room temperature using the photocurrent spectra for Ge concentration in the range x=0.12-0.20 and compared to similar data obtained by electroluminescence.