HIGH-SPEED, LONG-WAVELENGTH COHERENT RADIATION DETECTORS
Final technical rept. 15 May 1967-14 May 1968
TEXAS INSTRUMENTS INC DALLAS
Pagination or Media Count:
The first section deals with the appearance of dielectric relaxation time constant components. These arise when the drift length of holes becomes comparable to the electrode separation, so that a significant fraction of the photogenerated holes is swept from the crystal. Under these conditions, which correspond to having the photoconductive gain of the order of or greater than unity, there is a maximum D bandwidth product. The second section is concerned with the D bandwidth calculation and also points up the superiority of p-i-n diode performance over that of photoconductors if speed in excess of 10 to the minus 9th power second is required at 10.6 microns. In the third section gettering and contact effects are reported. It is shown that a gallium diffused layer getters copper from GeHg. Using radioactive copper, we have demonstrated a very irregular distribution of copper in the vicinity of the diffusion profile. Some general considerations on heterodyne detection form the fourth section of the report. Serious inefficiencies arise with misalignment of the local oscillator beam on an intrinsic photoconductor. A collinear mode of operation is shown to eliminate this effect, and studies of transparent contacts are reported. Finally, the loss of signal for misalignment of local oscillator and signal beams was calculated for a variety of detector sizes and 10.6 micron radiation.
- Lasers and Masers
- Infrared Detection and Detectors