A continuous composition spread approach towards monolithic, wavelength-selective multichannel UV-photo-detector arrays
- PDF / 296,613 Bytes
- 7 Pages / 432 x 648 pts Page_size
- 41 Downloads / 174 Views
A continuous composition spread approach towards monolithic, wavelength-selective multichannel UV-photo-detector arrays H. von Wenckstern, Z. Zhang, J. Lenzner, F. Schmidt and M. Grundmann Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany ABSTRACT Continuous composition spread (CCS) methods have been very successfully used for exploiting and optimization of new material systems. Concerning sample growth by pulsedlaser deposition (PLD) approaches towards thin films with a CCS are involved, here movable masks for partial shadowing of the substrate and multiple targets are needed to obtain linearly varying changes of composition. Here we make use of an approach allowing deposition of thin films with CCS at high growth rates by using segmented PLD targets. We describe how this approach can be used to fabricate monolithic, wavelength-selective multichannel UV-photodetector arrays. INTRODUCTION The detection of ultraviolet irradiation is important in environmental research and monitoring, flame detection and monitoring of industrial processes as UV curing of glues, adhesives or disinfection of drinking water by UV irradiation. Besides (Al,Ga)N semiconducting oxides present a material class that is very suited for realization of detectors operating in the UV-A, UV-B and even the UV-C spectral range. For most applications the determination of spectrally integrated UV radiation is not sufficient and a spectrally resolved detection of UV radiation is desired. Here, we demonstrate an approach towards monolithic wavelengthselective UV-A photo-detectors (PD) by using a continuous composition spread (CCS) approach.
Fig. 1: Schematics of the single target CCS-PLD method. Here, the case of a two-fold segmented target is depicted. Target and substrate rotation are synchronized. The center of the plasma
123
plume must have a spatial offset with respect to the center of the substrate for CCS formation.
Thin films with CCS have been created by various physical deposition methods such as magnetron sputtering and pulsed-laser deposition. Recently, we introduced a facile CCS technique for pulsed-laser deposition (PLD) that makes use of segmented PLD targets1. The use of such targets (cf. Fig. 1) makes partial shadowing of the substrates and time-consuming target changes as necessary in conventional PLD CCS approaches2 obsolete. In our segmented target CCS-PLD technique the growth rate, thickness distribution and the influence of the growth temperature is the same as for the deposition of laterally homogeneous thin films from a standard PLD target. Therefore, experience that has been gathered over long periods of time and that has been used to optimize an existing PLD setup is not lost but can instead be used to optimize thin film growth from segmented PLD targets. The resulting compositional gradient on the substrates depends on the background pressure (on the kinetics of the plasma expansion) and on geometrical parameters in particular the ta
Data Loading...
