You've shot yourself in the foot with the way you've designed your circuit. Just try it with a silicon diode, and if it's not reliable, use a germanium one. I've not looked at the product Datasheets but offered a potential solution on your circuit, it's up to you to go impliment and play. If you want to experiment at extremes, you've got a fridge, you've got an oven. Go test. Geeze, there's no guarantees in this world apart from death and taxes.