Irradiation of high resistivity p-like CdTe crystals pre-coated with an In dopant film from the CdTe side by nanosecond laser pulses with wavelength that is not absorbed by the semiconductor made it possible to directly affect the CdTe-In interface because radiation was strongly absorbed by a thin layer of the In film adjoining to the CdTe crystal. The doping mechanism was associated with the action of laser-induced stress wave which was generated under extreme conditions in the confined area at the CdTe-In interface under laser irradiation. The developed technique allowed avoiding evaporation of In dopant and resulted in the formation of the In-doped CdTe region and thus, creation of a built-in p-n junction. The temperature distribution inside the three layer CdTe-In-Water structure was calculated and correlations between the characteristics of the fabricated In/CdTe/Au diodes and laser processing conditions were obtained.
Laser-induced incandescence (LII) of carbon surface is investigated with 1.06 um YAG:Nd3+ pulsed laser excitation. The experiments show that the intensity of LII or carbon surface depends on the initial temperature of the investigated sample. A method is proposed for estimation of temperature of laser-heated surfaces. The method requires measurement of LII at a fixed wavelength with a moderate variation of initial sample temperature.
In this work the possibility of laser overheating of light-absorbing surfaces of bulk carbon samples to
incandescent temperatures with the use of a moderate-power Q-switched YAG-Nd3+ laser (wavelength 1064
nm, pulse duration 20 ns, power density 3-10 MW/cm2) was studied. We observed laser-induced incandescence
(LII) of carbon surfaces and investigated its properties. When the surface was irradiated by a sequence of laser
pulses, unusual changes of LII intensity were discovered in the experiments. Also significant nonlinearity in the
dependence of LII intensity on the laser pulse power density was observed. The average temperature of
irradiated surface was estimated by approximating the experimental LII spectrum by Plank's function and by
computer simulations of laser heating of the carbon surface. For typical experimental conditions, the value of
2400 K was obtained. Both of the estimates of temperature are in a good agreement. The model, which is
proposed to explain the observed effects, is based on the equation of heat conduction. Well-known thermal and
optical properties of carbon are taken into account. The observed effects can be explained by essential nonuniformity
of heating of rough surfaces and dominant evaporation of carbon from the tops of surface asperities.