Method for calorimetric absorption spectroscopy and device for working the method

US4429999A · kind A · utility

Inventors

• Dieter Bimberg · Aachen, DE
• Achim Bubenzer · Kirchzarten, DE
• Klaus Dransfeld · Kreuzlingen, CH
• Siegfried Hunklinger · Heidelberg, DE

Key dates

• Filing date: Jun 22, 1981
• Grant date: Feb 7, 1984
• Expiry date: Jun 22, 2001

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N21/171
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method of calorimetric absorption spectroscopy (CAS) is claimed, wherein a sample, irradiated with a measuring-light pulse of a specified power, duration, and wavelength and whose absorbance at the specific wavelength of the measuring light is determined as a result of the heating of the sample which occurs as a result of the absorption of a portion of the measuring light, is cooled to a temperature which is so low that the specific heat of the sample during measurement is only a small fraction of the value at normal temperature. This produces an increase in sensitivity by a factor of more than 10.sup.5. The manner in which the lifetime of radiant and nonradiant recombination can be determined in a simple fashion is claimed for samples which have a first impurity center, capable of recombination both by radiation and without radiation, and a second center, capable of recombination only without radiation. The temperature sensor in the sample chamber is placed in a cryostat suitable for working the method, and shielded hermetically against the measuring light and the scattered light resulting from the latter.