Avalanching in GaAs p-π-p structures

A reversible, electric breakdown at fields between 2 and 3 × 105 V cm is observed in p-type GaAs structures consisting of a high resistivity layer, approximately 1 μ thick, flanked by low resistivity regions. The breakdown is accompanied by light emission which takes place outside the high resistivity layer since the electrons produced by the breakdown process are swept into the adjacent low resistivity regions before they have a chance to recombine. A study of light intensity vs. electric field suggests an avalanche breakdown characterized by an ionization constant for holes which depends exponentially on the inverse electric field. These p-π-p structures are prepared by zinc diffusion into manganese doped (p-type) GaAs, and a mechanism is suggested for the formation of the high resistivity layer. The I-V characteristics before breakdown are essentially ohmic up to several volts suggesting the absence of space charge limitation for the current in such thin layers. © 1967.