cutting off power to a graphic LCD display

I am trying to save power by switching off graphics LCD(JHD12864E) when it is not required.
To do this I am using TIP122 as a switch. The base of the transistor is connected to a digital pin through a 1k resistor.
Collector is connected to GND of the LCD module.
Emitter is connected to Arduino GND.
Please see the diagram showing this.

I was hoping that by controlling the digital pin at transistor's base LCD can be switched off. BUT, the LCD display keeps flickering when digitalPin=1.

Is this the right way to switch off power to a peripheral device? If yes, then why is the display not stable? If not, please guide!

(Interestingly I found one guy had attempted this way...but had not succeeded either: http://electronics.stackexchange.com/questions/158096/control-lcd-with-tip121-on-arduino-not-displaying-anything)

Is this the right way to switch off power to a peripheral device?

No.
Because the signals going into the LCD produce parasitic powering of the device, as you have found. This is where the protection diodes on the inputs to the device leak current onto the supply rails and keep it powerd up after a fashion.
This is a very bad state of affairs and can damage the device, do not let it happen.

The correct way is to use a top switch to control the positive supply, normally a PNP transistor or p-channel FET. However just before you shut off the power you need to make all the signal lines going to the device into inputs to remove any chance of parasitic powering.