Making an AM radio with a silicon diode
There are many plans on the XTAL SET SOCIETY and Ben Tounge's websites, including both biasing of diodes for optimised detection and modeling of crystal radio circuits in SPICE.

Consider also using a Schottky diode (some of the HP types are fantastic for this and 'foxhole' razor blade diodes are essentially the same!) and zero-Vgs MOSFETs as reported about in Bob Cutler's 'High Sensitivity Crystal Radio Set' which is available online at the ARRL.

Of course, if you can get your Q high and tuning not so touchy and your local clear-channel is good enough, maybe that silicon diode is OK.